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GCSE 2019 Edexcel Foundation Paper 3
๐ Guide to Solutions
- ๐ก Understanding: Explains what the question is asking.
- โ Working: Shows the step-by-step mathematical method.
- โ Final Answer: Checks the result and gives the mark breakdown.
Table of Contents
- Question 1 (Rounding)
- Question 2 (Multiples)
- Question 3 (Conversions)
- Question 4 (Powers)
- Question 5 (Percentages)
- Question 6 (Percentages)
- Question 7 (Data Interpretation)
- Question 8 (Fractions)
- Question 9 (Algebra)
- Question 10 (Fractions)
- Question 11 (Money)
- Question 12 (Ratio)
- Question 13 (Sequences)
- Question 14 (Calculator)
- Question 15 (Formulae)
- Question 16 (Perimeter)
- Question 17 (Scale Drawing)
- Question 18 (Averages)
- Question 19 (Algebra)
- Question 20 (Geometry)
- Question 21 (Exchange Rates)
- Question 22 (Compound Measures)
- Question 23 (Ratio)
- Question 24 (Venn Diagrams)
- Question 25 (Compound Interest)
- Question 26 (Frequency Polygon)
- Question 27 (Graph Criticism)
- Question 28 (Polygon Angles)
- Question 29 (Surface Area)
- Question 30 (Simultaneous Equations)
Question 1 (1 mark)
Write \( 478 \) to the nearest hundred.
Worked Solution
Step 1: Understanding the rounding rule
๐ก What are we asked to do?
We need to round \( 478 \) to the nearest hundred. This means we are checking if \( 478 \) is closer to \( 400 \) or \( 500 \).
โ Working:
Identify the hundreds column (4) and the tens column (7).
The rule is: if the digit to the right (the tens digit) is \( 5 \) or more, we round up.
Here, the tens digit is \( 7 \), which is greater than \( 5 \).
So, we round up from \( 400 \) to \( 500 \).
Final Answer:
500
โ (B1)
Question 2 (1 mark)
Write down a multiple of \( 8 \) that is between \( 41 \) and \( 60 \).
Worked Solution
Step 1: Listing multiples of 8
๐ก What is a multiple?
A multiple of \( 8 \) is a number in the \( 8 \) times table.
โ Working:
Let’s list the multiples of \( 8 \):
\( 8, 16, 24, 32, 40, 48, 56, 64 \dots \)
Step 2: Checking the range
๐ก What range do we need?
We need a number between \( 41 \) and \( 60 \).
โ Working:
Looking at our list:
- \( 40 \) is too small (less than \( 41 \)).
- \( 48 \) is between \( 41 \) and \( 60 \).
- \( 56 \) is between \( 41 \) and \( 60 \).
- \( 64 \) is too big.
Final Answer:
You can write either:
48 or 56
โ (B1)
Question 3 (1 mark)
Change \( 1.5 \) kilometres to metres.
Worked Solution
Step 1: Knowing the conversion
๐ก How many metres in a kilometre?
There are \( 1000 \) metres in \( 1 \) kilometre.
To change from km to m, we multiply by \( 1000 \).
โ Working:
\[ 1.5 \times 1000 = 1500 \]Final Answer:
1500 metres
โ (B1)
Question 4 (1 mark)
Here is a list of numbers.
\( 4 \quad 6 \quad 9 \quad 10 \quad 15 \quad 27 \quad 30 \quad 40 \)
From the list, write down all the numbers that are powers of \( 3 \).
Worked Solution
Step 1: Identifying powers of 3
๐ก What is a power of 3?
A power of \( 3 \) is a number obtained by multiplying \( 3 \) by itself a certain number of times.
โ Working:
- \( 3^1 = 3 \)
- \( 3^2 = 3 \times 3 = 9 \)
- \( 3^3 = 3 \times 3 \times 3 = 27 \)
- \( 3^4 = 81 \)
Step 2: Checking the list
๐ก Which numbers from the list match?
We check our list of powers against the numbers given in the question.
โ Working:
Given: \( 4, 6, 9, 10, 15, 27, 30, 40 \)
- \( 9 \) matches \( 3^2 \).
- \( 27 \) matches \( 3^3 \).
Note: \( 6, 15, 30 \) are multiples of \( 3 \), but not powers of \( 3 \).
Final Answer:
9, 27
โ (B1)
Question 5 (1 mark)
Write \( 19\% \) as a fraction.
Worked Solution
Step 1: Understanding percent
๐ก What does “percent” mean?
“Percent” means “out of \( 100 \)”.
โ Working:
To convert a percentage to a fraction, we write the number over \( 100 \).
\[ 19\% = \frac{19}{100} \]This fraction cannot be simplified further as \( 19 \) is a prime number.
Final Answer:
\[ \frac{19}{100} \]
โ (B1)
Question 6 (2 marks)
Work out \( 20\% \) of \( 80 \).
Worked Solution
Step 1: Finding 10% first
๐ก Strategy:
A common way to find percentages without a calculator (though you can use one here) is to find \( 10\% \) first. To find \( 10\% \), we divide by \( 10 \).
โ Working:
\[ 10\% \text{ of } 80 = 80 \div 10 = 8 \]Step 2: Finding 20%
๐ก How do we get from 10% to 20%?
\( 20\% \) is double \( 10\% \). So we multiply our previous answer by \( 2 \).
โ Working:
\[ 20\% = 2 \times 10\% \] \[ 20\% \text{ of } 80 = 2 \times 8 = 16 \]Alternative Calculator Method:
Convert \( 20\% \) to a decimal (\( 0.2 \)) and multiply.
0.2 ร 80 = 16
Final Answer:
16
โ (M1 for method, A1 for answer)
Question 7 (2 marks)
There are four types of counter in a bag.
The table shows the number of each type of counter in the bag.
| Type of counter | red circle | green circle | red square | green square |
|---|---|---|---|---|
| Number of counters | 16 | 26 | 11 | 7 |
There are more green counters than red counters.
How many more?
Worked Solution
Step 1: Calculate total green counters
๐ก Which columns represent green counters?
We need to look for “green circle” and “green square”.
โ Working:
Green circles: \( 26 \)
Green squares: \( 7 \)
\[ \text{Total Green} = 26 + 7 = 33 \]Step 2: Calculate total red counters
๐ก Which columns represent red counters?
We need “red circle” and “red square”.
โ Working:
Red circles: \( 16 \)
Red squares: \( 11 \)
\[ \text{Total Red} = 16 + 11 = 27 \]Step 3: Find the difference
๐ก What does “how many more” mean?
It means we need to subtract the smaller number from the larger number.
โ Working:
\[ 33 – 27 = 6 \]Final Answer:
6
โ (M1 for totals, A1 for answer)
Question 8 (3 marks)
Here is the gauge for the fuel tank of a car.
The fuel tank holds \( 52 \) litres of fuel when the tank is full.
The tank is \( \frac{1}{4} \) full of fuel.
Work out how many more litres of fuel are needed to fill the tank.
Worked Solution
Step 1: Calculate current fuel
๐ก What do we know?
The total capacity is \( 52 \) litres. The tank currently has \( \frac{1}{4} \) of this amount.
โ Working:
To find \( \frac{1}{4} \) of \( 52 \), we divide by \( 4 \).
\[ 52 \div 4 = 13 \]So, there are \( 13 \) litres in the tank.
Step 2: Calculate fuel needed
๐ก How much more is needed?
We need to fill it up to \( 52 \) litres. We subtract what we have from the total.
โ Working:
\[ \text{Needed} = \text{Total} – \text{Current} \] \[ 52 – 13 = 39 \]Alternative Method
๐ก Thinking about fractions
If the tank is \( \frac{1}{4} \) full, then it is \( \frac{3}{4} \) empty.
We need to find \( \frac{3}{4} \) of \( 52 \).
โ Working:
\[ \frac{1}{4} \text{ of } 52 = 13 \] \[ \frac{3}{4} \text{ of } 52 = 13 \times 3 = 39 \]Final Answer:
39 litres
โ (M1 for finding 1/4, M1 for subtraction method, A1 for answer)
Question 9 (2 marks)
Simplify \( 4e + 6f + 7e – f \)
Worked Solution
Step 1: Group like terms
๐ก What are like terms?
Like terms are terms that have the same variable (letter). We can collect the ‘e’ terms and the ‘f’ terms separately.
Remember that the sign before the term belongs to that term.
โ Working:
\( e \) terms: \( 4e + 7e \)
\( f \) terms: \( +6f – f \) (Note: \( -f \) is the same as \( -1f \))
Step 2: Simplify
๐ก Combine the coefficients
Add the numbers in front of the letters.
โ Working:
\[ 4e + 7e = 11e \] \[ 6f – 1f = 5f \]Putting it back together:
\[ 11e + 5f \]Final Answer:
\( 11e + 5f \)
โ (M1 for 11e or 5f, A1 for correct expression)
Question 10 (3 marks)
Bill has \( 400 \) counters in a bag.
He gives:
- \( 35 \) of the counters to Sameena
- \( 50 \) of the counters to Henry
- \( 75 \) of the counters to Lucas
What fraction of the \( 400 \) counters is left in Bill’s bag?
Give your fraction in its simplest form.
Worked Solution
Step 1: Calculate total counters given away
๐ก How many did he give in total?
Add up the amounts given to Sameena, Henry, and Lucas.
โ Working:
\[ 35 + 50 + 75 = 160 \]Step 2: Calculate counters left
๐ก How many remain?
Subtract the total given away from the starting amount.
โ Working:
\[ 400 – 160 = 240 \]Step 3: Write as a fraction
๐ก Format: Part over Whole
The question asks for the fraction left out of the total.
โ Working:
\[ \frac{240}{400} \]Step 4: Simplify the fraction
๐ก Reduce to simplest form
Divide top and bottom by common factors until you can’t go further.
โ Working:
Divide by 10 (cancel zeros):
\[ \frac{24}{40} \]Divide by 8 (highest common factor):
\[ 24 \div 8 = 3 \] \[ 40 \div 8 = 5 \]Result:
\[ \frac{3}{5} \]Final Answer:
\[ \frac{3}{5} \]
โ (M1 for totals, M1 for subtraction fraction, A1 for simplified answer)
Question 11 (4 marks)
The table shows the costs of sending a parcel by the Express service and by the Rapid service.
| Type of service | Cost |
|---|---|
| Express | ยฃ15.25 |
| Rapid | ยฃ35.38 |
Brendan has to send \( 12 \) parcels.
It will be cheaper to send the parcels by the Express service than by the Rapid service.
(a) How much cheaper?
Worked Solution (a)
Step 1: Calculate cost for 1 parcel difference
๐ก Strategy:
We can find the difference in cost for one parcel first, then multiply by the number of parcels.
โ Working:
\[ \text{Difference per parcel} = 35.38 – 15.25 = 20.13 \]Step 2: Calculate total difference
๐ก Multiply by quantity
Multiply the difference per parcel by the number of parcels (\( 12 \)).
โ Working:
\[ 20.13 \times 12 = 241.56 \]Alternative Method
๐ก Calculate totals separately
Calculate the total cost for Express for all parcels, then the total for Rapid, and find the difference.
โ Working:
Total Express: \( 15.25 \times 12 = 183.00 \)
Total Rapid: \( 35.38 \times 12 = 424.56 \)
Difference: \( 424.56 – 183.00 = 241.56 \)
Final Answer (a):
ยฃ241.56
โ (P1 for diff, P1 for total process, A1 cao)
Luke wants to send \( 21 \) parcels by the Express service.
He does the calculation \( 20 \times ยฃ15 = ยฃ300 \) to estimate the cost.
(b) Explain why Luke’s calculation shows the actual cost will be more than ยฃ300.
Worked Solution (b)
Step 1: Analyze the rounding
๐ก What did Luke round?
He rounded \( 21 \) down to \( 20 \).
He rounded \( 15.25 \) down to \( 15 \).
Step 2: Formulate the explanation
๐ก How does rounding affect the total?
If you round both numbers down, the result will be smaller than the actual answer.
โ Explanation:
Luke rounded both numbers down (21 to 20 and 15.25 to 15). Therefore, his estimate is an underestimate.
Or: “21 is greater than 20 and 15.25 is greater than 15, so the actual cost involves multiplying larger numbers.”
Final Answer (b):
“He rounded both values down, so the estimate is lower than the actual cost.”
โ (C1)
Question 12 (2 marks)
Ali, Ben and Cathy share an amount of money in the ratio \( 6 : 9 : 10 \)
What fraction of the money does Ben get?
Worked Solution
Step 1: Understand Ratio Parts
๐ก Identify the parts
The ratio is \( 6 : 9 : 10 \).
- Ali gets \( 6 \) parts.
- Ben gets \( 9 \) parts.
- Cathy gets \( 10 \) parts.
Step 2: Calculate Total Parts
๐ก The “Whole”
To make a fraction, the denominator (bottom number) is the total number of parts.
โ Working:
\[ \text{Total Parts} = 6 + 9 + 10 = 25 \]Step 3: Form the Fraction
๐ก Part over Whole
Ben gets \( 9 \) parts out of \( 25 \) total parts.
โ Working:
\[ \text{Fraction for Ben} = \frac{9}{25} \]Final Answer:
\[ \frac{9}{25} \]
โ (M1 for total parts, A1 for fraction)
Question 13 (2 marks)
The first term of a sequence of numbers is \( 24 \)
The term-to-term rule of this sequence is ‘add \( 8 \)’
Josie says,
“No number in this sequence is in the \( 5 \) times table.”
(a) Give an example to show that Josie is wrong.
Worked Solution (a)
Step 1: Generate the sequence
๐ก List the terms
Start at \( 24 \) and keep adding \( 8 \).
โ Working:
1st term: \( 24 \)
2nd term: \( 24 + 8 = 32 \)
3rd term: \( 32 + 8 = 40 \)
4th term: \( 40 + 8 = 48 \)
5th term: \( 48 + 8 = 56 \)
6th term: \( 56 + 8 = 64 \)
7th term: \( 64 + 8 = 72 \)
8th term: \( 72 + 8 = 80 \)
Step 2: Find a multiple of 5
๐ก What is in the 5 times table?
Numbers ending in \( 0 \) or \( 5 \).
โ Working:
\( 40 \) ends in \( 0 \), so it is a multiple of \( 5 \).
\( 80 \) ends in \( 0 \), so it is a multiple of \( 5 \).
Final Answer (a):
40 (or 80)
โ (C1)
(b) Is \( 85 \) a number in this sequence?
Give a reason for your answer.
Worked Solution (b)
Step 1: Analyze the sequence properties
๐ก Even vs Odd
The sequence starts with an even number (\( 24 \)) and we add an even number (\( 8 \)).
Even + Even = Even.
โ Reasoning:
All numbers in the sequence are even because we start with an even number and add \( 8 \) repeatedly.
\( 85 \) is an odd number.
Alternative Method: Formula
๐ก Multiples of 8
All terms in the sequence are multiples of \( 8 \).
\( 24 \) is \( 3 \times 8 \).
Adding \( 8 \) keeps it a multiple of \( 8 \).
โ Working:
\( 80 \) is a multiple of \( 8 \). The next term is \( 88 \).
\( 85 \) is not a multiple of \( 8 \).
Final Answer (b):
No.
Reason: 85 is an odd number and all numbers in the sequence are even.
โ (C1)
Question 14 (2 marks)
Find the value of \( \frac{5.27 + 3.5}{7.9 – 4.36} \)
Give your answer as a decimal.
Write down all the figures on your calculator display.
Worked Solution
Step 1: Calculate numerator and denominator separately
๐ก Order of Operations (BIDMAS)
The fraction bar acts like brackets. We must calculate the top and bottom before dividing.
โ Working:
Top (Numerator): \( 5.27 + 3.5 = 8.77 \)
Bottom (Denominator): \( 7.9 – 4.36 = 3.54 \)
Step 2: Perform the division
๐ก Use Calculator
Divide the top result by the bottom result.
โ Working:
\[ 8.77 \div 3.54 = 2.4774011299… \]Final Answer:
2.4774011…
(Accept 2.4774 or better)
โ (M1 for 8.77 or 3.54 seen, A1 for full decimal)
Question 15 (4 marks)
You can use this rule to work out the total hire charge, in pounds (ยฃ), for hiring a 3D printer for a number of weeks.
Mia wants to hire a 3D printer for \( 4 \) weeks.
(a) Work out the total hire charge.
Worked Solution (a)
Step 1: Substitute the value into the formula
๐ก Replace “number of weeks”
We are given \( 4 \) weeks, so replace “number of weeks” with \( 4 \).
โ Working:
\[ \text{Total Charge} = 4 \times 70 + 50 \]Step 2: Calculate
๐ก Order of Operations (BIDMAS)
Multiply before adding.
โ Working:
\[ 4 \times 70 = 280 \] \[ 280 + 50 = 330 \]Final Answer (a):
ยฃ330
โ (M1 for substitution, A1 cao)
Zahir hires a 3D printer.
The total hire charge is \( ยฃ680 \)
(b) For how many weeks does Zahir hire the 3D printer?
Worked Solution (b)
Step 1: Set up the equation
๐ก Work backwards
We know the total cost is \( 680 \). We need to find the number of weeks (let’s call it \( w \)).
โ Working:
\[ w \times 70 + 50 = 680 \]Step 2: Solve for weeks
๐ก Inverse operations
To undo “add 50”, we subtract 50.
To undo “multiply by 70”, we divide by 70.
โ Working:
Subtract 50:
\[ 680 – 50 = 630 \]Divide by 70:
\[ 630 \div 70 = 9 \]Final Answer (b):
9 weeks
โ (M1 for inverse operations, A1 cao)
Question 16 (3 marks)
Here is a rectangle.
The 6-sided shape below is made from two of these rectangles.
Work out the perimeter of this 6-sided shape.
Worked Solution
Step 1: Understand the dimensions
๐ก Analyze the shape
The shape is made of two identical rectangles. Each rectangle is \( 6 \text{ cm} \) by \( 4 \text{ cm} \).
We need to find the length of every outer side to calculate the perimeter.
โ Identifying sides:
- Left vertical side: \( 6 \text{ cm} \) (long side of vertical rectangle)
- Top horizontal side: \( 4 \text{ cm} \) (short side of vertical rectangle)
- Right vertical side (top part): This is part of the vertical rectangle’s side.
- Right vertical side (bottom part): This is the short side of the horizontal rectangle (\( 4 \text{ cm} \)).
- Bottom horizontal side: This is the long side of the horizontal rectangle (\( 6 \text{ cm} \)).
Step 2: Find missing lengths
๐ก Calculating the hidden lengths
Let’s trace the perimeter clockwise from the top-left corner.
โ Working:
- Top: \( 4 \text{ cm} \)
- Right-inner vertical: The total height on the left is \( 6 \). The height of the horizontal rectangle on the right is \( 4 \). So the vertical bit sticking up is \( 6 – 4 = 2 \text{ cm} \).
- Top-inner horizontal: The total width on the bottom is the width of the vertical rect (\( 4 \)) plus the part sticking out. Wait, let’s look at the join.
Correct Logic:
- Left side: \( 6 \)
- Top side: \( 4 \)
- Inner vertical down: \( 6 – 4 = 2 \) (because the side of the horizontal rect is 4)
- Inner horizontal right: \( 6 \) (length of horizontal rect)
- Far right side: \( 4 \) (width of horizontal rect)
- Bottom side: The total width. The vertical rect is \( 4 \) wide. The horizontal rect is \( 6 \) long. They are joined at the corner? No, look at the shape.
Let’s assume standard “L” shape formation:
- Top: \( 4 \)
- Left: \( 6 \)
- Bottom: \( 4 + 6 = 10 \)
- Right: \( 4 \)
- Inner horizontal: \( 6 \)
- Inner vertical: \( 2 \)
Let’s sum the outer boundary:
\( 4 \) (top) \( + 2 \) (inner vertical) \( + 6 \) (inner horizontal) \( + 4 \) (right) \( + 6 \) (bottom part) \( + 4 \) (bottom part? No, let’s re-read diagram).
Actually, simpler method: The perimeter of an L-shape made from two rectangles is often equal to the perimeter of the bounding box.
Total Height = \( 6 \) cm.
Total Width = \( 4 \) cm (width of first) + \( 6 \) cm (length of second) = \( 10 \) cm.
Perimeter = \( 2 \times (10 + 6) = 32 \) cm?
Let’s verify side by side:
- Top: \( 4 \)
- Right-down (partial): \( 6 – 4 = 2 \)
- Right-across (top of horizontal rect): \( 6 \)
- Right-down (side of horizontal rect): \( 4 \)
- Bottom: \( 4 + 6 = 10 \) (Wait, diagram shows they are flush left? No, usually corner to corner).
Let’s assume the standard L-shape:
- Top edge: \( 4 \)
- Left edge: \( 6 \)
- Right edge (bottom part): \( 4 \)
- Bottom edge: \( 6 \) (of the horizontal rect) + \( 4 \) (of the vertical rect)? No.
Let’s trace carefully:
1. Top of vertical rect: \( 4 \)
2. Left of vertical rect: \( 6 \)
3. Bottom of vertical rect (hidden part) + Bottom of horizontal rect: The shape is fused.
Let’s assume standard join (corner to corner):
Perimeter = \( 6 \) (left) + \( 4 \) (top) + \( 2 \) (inner vertical) + \( 6 \) (top of horizontal) + \( 4 \) (right) + \( (4 + 6) \) (bottom)? No, that doesn’t close.
Correct Summation:
Let’s list the 6 sides:
1. Left: \( 6 \)
2. Top: \( 4 \)
3. Inner Vertical: \( 6 – 4 = 2 \)
4. Inner Horizontal: \( 6 \)
5. Right: \( 4 \)
6. Bottom: \( 4 + 6 = 10 \)
Sum: \( 6 + 4 + 2 + 6 + 4 + 10 = 32 \)
Final Answer:
32 cm
โ (P1 for process, A1 cao)
Question 17 (2 marks)
The accurate scale diagram shows a telephone mast and a box.
The box has a real width of \( 1.5 \) metres.
Find an estimate for the real height, in metres, of the telephone mast.
Worked Solution
Step 1: Determine the scale
๐ก Measure the diagram
Since we are on a screen, we must rely on relative sizes.
Visually compare the width of the box to the height of the mast.
The width of the box represents \( 1.5 \) m.
โ Working:
Let’s count how many “boxes” fit into the height of the mast.
If you stack the box on top of each other, it looks like it fits about \( 6 \) times.
Step 2: Calculate the estimate
๐ก Multiply
Multiply the real width of the box by the scale factor we found.
โ Working:
\[ \text{Height} \approx 6 \times 1.5 \] \[ 6 \times 1.5 = 9 \]Final Answer:
9 metres
(Accept answers in range 8 to 10)
โ (M1 for scale method, A1 for answer)
Question 18 (3 marks)
The table shows information about the numbers of points scored by \( 30 \) students in a quiz.
| Number of points | Frequency |
|---|---|
| 0 | 4 |
| 1 | 3 |
| 2 | 7 |
| 3 | 5 |
| 4 | 6 |
| 5 | 5 |
(a) Find the modal number of points.
Worked Solution (a)
Step 1: Identify the Mode
๐ก What is the Mode?
The mode is the value with the highest frequency (the most common score).
โ Working:
Look at the “Frequency” column. The highest number is \( 7 \).
The score associated with frequency \( 7 \) is \( 2 \).
Final Answer (a):
2
โ (B1)
(b) Work out the total number of points scored.
Worked Solution (b)
Step 1: Calculate points for each row
๐ก Why multiply?
Since \( 4 \) students scored \( 0 \), that’s \( 0 \) points total.
Since \( 3 \) students scored \( 1 \), that’s \( 3 \) points total.
We need to multiply Points ร Frequency for each row.
โ Working:
- \( 0 \times 4 = 0 \)
- \( 1 \times 3 = 3 \)
- \( 2 \times 7 = 14 \)
- \( 3 \times 5 = 15 \)
- \( 4 \times 6 = 24 \)
- \( 5 \times 5 = 25 \)
Step 2: Sum the totals
๐ก Add them all up
Find the sum of all the points calculated in step 1.
โ Working:
\[ 0 + 3 + 14 + 15 + 24 + 25 = 81 \]Final Answer (b):
81
โ (M1 for fx method, A1 cao)
Question 19 (2 marks)
Make \( x \) the subject of the formula \( y = 2x + 4 \)
Worked Solution
Step 1: Isolate the x term
๐ก Move the constant
We want \( x \) on its own. First, move the \( +4 \) to the other side by subtracting \( 4 \).
โ Working:
\[ y – 4 = 2x \]Step 2: Solve for x
๐ก Divide by the coefficient
Currently \( x \) is multiplied by \( 2 \). To undo this, divide the whole equation by \( 2 \).
โ Working:
\[ \frac{y – 4}{2} = x \]Or written as:
\[ x = \frac{y – 4}{2} \]Final Answer:
\[ x = \frac{y – 4}{2} \]
โ (M1 for inverse operation, A1 cao)
Question 20 (2 marks)
The diagram shows a square \( ABDE \) and an equilateral triangle \( BCD \).
Work out the size of angle \( EBC \).
Worked Solution
Step 1: Find angle EBD
๐ก Properties of a Square
\( ABDE \) is a square. The diagonal \( EB \) cuts the corner angle (\( 90^\circ \)) in half.
โ Working:
Angle \( ABD = 90^\circ \).
Angle \( EBD = 90^\circ \div 2 = 45^\circ \).
Step 2: Find angle DBC
๐ก Properties of an Equilateral Triangle
\( BCD \) is an equilateral triangle. All angles in an equilateral triangle are \( 60^\circ \).
โ Working:
Angle \( DBC = 60^\circ \).
Step 3: Calculate total angle EBC
๐ก Add the parts
Angle \( EBC \) is the sum of angle \( EBD \) and angle \( DBC \).
โ Working:
\[ 45^\circ + 60^\circ = 105^\circ \]Final Answer:
105ยฐ
โ (M1 for property used, A1 cao)
Question 21 (3 marks)
Liz goes on holiday to South Africa.
Liz wants to change \( ยฃ850 \) into South African rand.
She wants to get as many \( 200 \) rand notes as possible.
The exchange rate is \( ยฃ1 = 18.53 \) rand.
Work out the greatest number of \( 200 \) rand notes that Liz can get for \( ยฃ850 \).
Worked Solution
Step 1: Convert GBP to Rand
๐ก Multiply by the exchange rate
To change pounds into foreign currency, we multiply by the rate.
โ Working:
\[ 850 \times 18.53 = 15750.5 \text{ rand} \]Step 2: Find how many 200 notes fit
๐ก Divide by note value
We need to see how many times \( 200 \) goes into the total rand amount.
โ Working:
\[ 15750.5 \div 200 = 78.7525 \]Step 3: Round down to nearest whole note
๐ก Can you have part of a note?
No, you can only get whole notes. We must round down (truncate) because she doesn’t have enough for the 79th note.
โ Working:
\( 78.75… \) rounds down to \( 78 \).
Final Answer:
78
โ (P1 for conversion, P1 for division, A1 cao)
Question 22 (4 marks)
In October Sally drove \( 560 \) miles in her car.
The car travelled \( 34.5 \) miles for each gallon of petrol used.
Petrol cost \( ยฃ1.08 \) per litre.
\( 1 \text{ gallon} = 4.55 \text{ litres} \).
Work out the cost of the petrol the car used in October.
Worked Solution
Step 1: Calculate gallons used
๐ก Divide total miles by miles per gallon
We know how far she went (\( 560 \)) and how far one gallon takes her (\( 34.5 \)).
โ Working:
\[ 560 \div 34.5 = 16.23188… \text{ gallons} \]Keep the full number on your calculator.
Step 2: Convert gallons to litres
๐ก Multiply by conversion factor
There are \( 4.55 \) litres in every gallon.
โ Working:
\[ 16.23188… \times 4.55 = 73.85507… \text{ litres} \]Step 3: Calculate total cost
๐ก Multiply litres by price per litre
Each litre costs \( ยฃ1.08 \).
โ Working:
\[ 73.85507… \times 1.08 = 79.7634… \]Step 4: Round to currency
๐ก Two decimal places
Money is always rounded to 2 decimal places.
โ Working:
\[ ยฃ79.76 \]Final Answer:
ยฃ79.76
โ (P1 for gallons, P1 for litres, P1 for cost, A1 in range 79.69-79.79)
Question 23 (5 marks)
Costcorp sells packets of mints to shop owners.
On Monday three shop owners buy mints from Costcorp.
Each shop owner buys small packets, medium packets and large packets of mints.
Alan buys 400 packets of mints.
- \( 32\% \) are small packets.
- \( 40\% \) are large packets.
Beryl buys 500 packets of mints.
- \( \frac{3}{10} \) are small packets.
- \( \frac{1}{10} \) are large packets.
Charlie buys 150 small packets of mints so that
number of small packets : number of medium packets = \( 3 : 4 \)
Work out the total number of medium packets of mints these shop owners buy.
You must show all your working.
Worked Solution
Step 1: Calculate Alan’s medium packets
๐ก Find the percentage of medium first
We know \( 32\% \) are small and \( 40\% \) are large. The rest must be medium.
Total percentage is \( 100\% \).
โ Working:
\[ 100\% – (32\% + 40\%) = 100\% – 72\% = 28\% \]Now calculate \( 28\% \) of \( 400 \):
\[ 0.28 \times 400 = 112 \text{ medium packets} \]Step 2: Calculate Beryl’s medium packets
๐ก Find the fraction of medium first
We know \( \frac{3}{10} \) are small and \( \frac{1}{10} \) are large.
Total fraction is \( 1 \) (or \( \frac{10}{10} \)).
โ Working:
\[ 1 – (\frac{3}{10} + \frac{1}{10}) = 1 – \frac{4}{10} = \frac{6}{10} \]Now calculate \( \frac{6}{10} \) of \( 500 \):
\[ \frac{6}{10} \times 500 = 6 \times 50 = 300 \text{ medium packets} \]Step 3: Calculate Charlie’s medium packets
๐ก Use the ratio
Ratio of Small : Medium = \( 3 : 4 \)
We are told Charlie has \( 150 \) small packets. This represents the ‘3’ parts.
โ Working:
Value of 1 part:
\[ 150 \div 3 = 50 \]Medium packets (4 parts):
\[ 50 \times 4 = 200 \text{ medium packets} \]Step 4: Calculate total medium packets
๐ก Sum the results
Add Alan’s, Beryl’s, and Charlie’s medium packets together.
โ Working:
\[ 112 + 300 + 200 = 612 \]Final Answer:
612
โ (P1 for Alan, P1 for Beryl, P1 for Charlie, P1 for total, A1 cao)
Question 24 (5 marks)
\( \mathscr{E} = \{1, 2, 3, 4, 5, 6, 7, 8, 9\} \)
\( A = \{1, 5, 6, 8, 9\} \)
\( B = \{2, 6, 9\} \)
(a) Complete the Venn diagram to represent this information.
Worked Solution (a)
Step 1: Find the Intersection (Middle)
๐ก What is in both A and B?
Look for numbers that appear in both lists.
\( A = \{1, 5, \mathbf{6}, 8, \mathbf{9}\} \)
\( B = \{2, \mathbf{6}, \mathbf{9}\} \)
The intersection contains \( 6 \) and \( 9 \).
Step 2: Fill the rest of A
๐ก A only
Numbers in A that are NOT in B.
\( 1, 5, 8 \)
Step 3: Fill the rest of B
๐ก B only
Numbers in B that are NOT in A.
\( 2 \)
Step 4: Fill the Outside
๐ก Outside A and B
Check the universal set \( \mathscr{E} \) for numbers not used yet.
\( \mathscr{E} = \{1, 2, 3, 4, 5, 6, 7, 8, 9\} \)
Used: \( 1, 2, 5, 6, 8, 9 \)
Leftover: \( 3, 4, 7 \)
Final Answer (a):
Check diagram above.
โ (C1 for correctly placing all numbers)
A number is chosen at random from the universal set \( \mathscr{E} \).
(b) Find the probability that the number is in the set \( A \cap B \)
Worked Solution (b)
Step 1: Identify the target set
๐ก What is \( A \cap B \)?
This symbol \( \cap \) means “Intersection”. It asks for numbers in both A and B.
From our diagram, these are \( \{6, 9\} \).
There are \( 2 \) numbers.
Step 2: Calculate Probability
๐ก Successes / Total
There are \( 9 \) numbers in total in the universal set.
โ Working:
\[ P(A \cap B) = \frac{2}{9} \]Final Answer (b):
\[ \frac{2}{9} \]
โ (M1 for identifying 2 or 9, A1 cao)
Question 25 (3 marks)
Katy invests \( ยฃ200,000 \) in a savings account for \( 4 \) years.
The account pays compound interest at a rate of \( 1.5\% \) per annum.
Calculate the total amount of interest Katy will get at the end of \( 4 \) years.
Worked Solution
Step 1: Find the multiplier
๐ก Convert percentage increase to decimal
An increase of \( 1.5\% \) means we have \( 100\% + 1.5\% = 101.5\% \).
As a decimal, this is \( 1.015 \).
Step 2: Calculate the total amount after 4 years
๐ก Formula: Original ร Multiplier^Years
โ Working:
\[ 200,000 \times 1.015^4 \]200000 ร 1.015^4 = 212272.7101...
Step 3: Calculate the interest ONLY
๐ก Subtract the original investment
The question asks for the interest, not the total amount.
โ Working:
\[ 212,272.71 – 200,000 = 12,272.71 \]Final Answer:
ยฃ12,272.71
โ (M1 for multiplier, M1 for compound calculation, A1 cao)
Question 26 (3 marks)
The table shows information about the heights of \( 80 \) plants.
| Height (\( h \) cm) | Frequency |
|---|---|
| \( 10 < h \le 20 \) | 7 |
| \( 20 < h \le 30 \) | 13 |
| \( 30 < h \le 40 \) | 14 |
| \( 40 < h \le 50 \) | 12 |
| \( 50 < h \le 60 \) | 16 |
| \( 60 < h \le 70 \) | 18 |
(a) Find the class interval that contains the median.
Worked Solution (a)
Step 1: Find the median position
๐ก Total frequency / 2
There are \( 80 \) plants. The median is the \( \frac{80+1}{2} = 40.5 \)-th value.
We need to find which group the 40th/41st plant is in.
Step 2: Cumulative frequency
๐ก Add up the frequencies
Keep adding the counts until we pass \( 40.5 \).
โ Working:
- \( 10 < h \le 20 \): \( 7 \) (Total 7)
- \( 20 < h \le 30 \): \( 7 + 13 = 20 \) (Total 20)
- \( 30 < h \le 40 \): \( 20 + 14 = 34 \) (Total 34)
- \( 40 < h \le 50 \): \( 34 + 12 = 46 \) (Total 46)
The 40th value is in the \( 40 < h \le 50 \) group.
Final Answer (a):
\( 40 < h \le 50 \)
โ (B1)
(b) On the grid, draw a frequency polygon for the information in the table.
Worked Solution (b)
Step 1: Determine Plotting Points
๐ก Use Midpoints
For a frequency polygon, we plot the frequency against the midpoint of each class interval.
โ Midpoints:
- \( 10-20 \rightarrow 15 \)
- \( 20-30 \rightarrow 25 \)
- \( 30-40 \rightarrow 35 \)
- \( 40-50 \rightarrow 45 \)
- \( 50-60 \rightarrow 55 \)
- \( 60-70 \rightarrow 65 \)
Step 2: Plot and Join
๐ก Join with straight lines
Plot the points: \( (15, 7), (25, 13), (35, 14), (45, 12), (55, 16), (65, 18) \).
Connect them with straight line segments.
Final Answer (b):
See the red line on the graph above.
โ (B2 for correct points joined with lines)
Question 27 (2 marks)
Sean has drawn a time series graph to show the numbers, in thousands, of visitors to a fun park.
Write down two things that are wrong or could be misleading with this graph.
Worked Solution
Step 1: Inspect the Y-axis (Vertical)
๐ก Check the scale
Look at the numbers going up: \( 6, 6.5, 7, 7.5, 8, 8.5, 9, 10 \).
The gap between \( 8.5 \) and \( 9 \) is the same visual size as \( 9 \) to \( 10 \), but represents \( 0.5 \) vs \( 1.0 \).
Also, the graph does not start at \( 0 \) (truncation), which can exaggerate changes, although it’s labelled \( 6 \).
Step 2: Inspect the X-axis (Horizontal)
๐ก Check the labels
The labels are \( 2, 3, 4 \) for each year. What happened to quarter \( 1 \)?
The points are plotted, but connected with a curve. Time series points are usually connected with straight lines.
Final Answer:
Any two of the following:
- The vertical scale is non-linear (jumps from 9 to 10).
- The graph should be joined with straight lines, not a curve.
- Quarter 1 is missing from the x-axis.
- The y-axis does not start at 0 (or show a break symbol).
โ (B2)
Question 28 (4 marks)
The diagram shows a hexagon.
The hexagon has one line of symmetry.
\( FA = BC \)
\( EF = CD \)
Angle \( ABC = 117^\circ \)
Angle \( BCD = 2 \times \) angle \( CDE \)
Work out the size of angle \( AFE \).
You must show all your working.
Worked Solution
Step 1: Use Symmetry
๐ก Angles match on both sides
Since there is a line of symmetry:
- Angle \( FAB = \) Angle \( CBA = 117^\circ \)
- Angle \( CDE = \) Angle \( DEF \)
- Angle \( BCD = \) Angle \( AFE \)
Step 2: Calculate sum of interior angles
๐ก Formula: (n-2) ร 180
A hexagon has \( 6 \) sides (\( n=6 \)).
โ Working:
\[ (6 – 2) \times 180 = 4 \times 180 = 720^\circ \]Step 3: Set up an equation
๐ก Define variables
Let Angle \( CDE = x \). Then Angle \( DEF = x \).
We are told Angle \( BCD = 2 \times \) Angle \( CDE \), so Angle \( BCD = 2x \).
By symmetry, Angle \( AFE = 2x \).
โ Equation:
Sum of angles = \( 720^\circ \)
\[ 117 + 117 + 2x + 2x + x + x = 720 \] \[ 234 + 6x = 720 \]Step 4: Solve for x
๐ก Rearrange and solve
โ Working:
\[ 6x = 720 – 234 \] \[ 6x = 486 \] \[ x = 486 \div 6 = 81^\circ \]Step 5: Find angle AFE
๐ก Substitute back
We need Angle \( AFE \), which is \( 2x \).
โ Working:
\[ 2 \times 81 = 162^\circ \]Final Answer:
162ยฐ
โ (M1 for sum of angles, M1 for equation, M1 for solving, A1 cao)
Question 29 (5 marks)
Jeremy has to cover \( 3 \) tanks completely with paint.
Each tank is in the shape of a cylinder with a top and a bottom.
The tank has a diameter of \( 1.6 \) m and a height of \( 1.8 \) m.
Jeremy has \( 7 \) tins of paint.
Each tin of paint covers \( 5 \text{ m}^2 \).
Has Jeremy got enough paint to cover completely the \( 3 \) tanks?
You must show how you get your answer.
Worked Solution
Step 1: Calculate Surface Area of one tank
๐ก Formula for Cylinder Surface Area
Surface Area = \( 2 \pi r^2 \) (top and bottom circles) + \( 2 \pi r h \) (curved side).
Diameter = \( 1.6 \text{ m} \), so Radius (\( r \)) = \( 0.8 \text{ m} \).
Height (\( h \)) = \( 1.8 \text{ m} \).
โ Working:
Area of circles (top + bottom):
\[ 2 \times \pi \times 0.8^2 = 2 \times \pi \times 0.64 = 1.28\pi \approx 4.021… \text{ m}^2 \]Area of curved side:
\[ 2 \times \pi \times 0.8 \times 1.8 = 2.88\pi \approx 9.047… \text{ m}^2 \]Total Area for 1 tank:
\[ 4.021 + 9.047 = 13.069… \text{ m}^2 \]Step 2: Calculate total area for 3 tanks
๐ก Multiply by 3
โ Working:
\[ 13.069… \times 3 = 39.207… \text{ m}^2 \]Step 3: Calculate paint coverage
๐ก Total coverage available
Jeremy has \( 7 \) tins, each covering \( 5 \text{ m}^2 \).
โ Working:
\[ 7 \times 5 = 35 \text{ m}^2 \]Step 4: Compare and Conclude
๐ก Is coverage > area needed?
โ Working:
Area needed: \( 39.2 \text{ m}^2 \)
Paint available: \( 35 \text{ m}^2 \)
\( 35 < 39.2 \), so he does not have enough.
Final Answer:
No.
He needs coverage for 39.2 mยฒ, but only has enough for 35 mยฒ.
โ (P1 area circles, P1 curved area, P1 total area, P1 total paint, C1 conclusion)
Question 30 (3 marks)
Solve the simultaneous equations
\( 3x – 4y = 11 \)
\( 9x + 2y = 5 \)
Worked Solution
Step 1: Eliminate one variable
๐ก Strategy: Match coefficients
Equation 1: \( 3x – 4y = 11 \)
Equation 2: \( 9x + 2y = 5 \)
Let’s make the \( y \) coefficients match (ignoring signs). Multiply Eq 2 by \( 2 \).
โ Working:
Eq 2 \( \times 2 \):
\[ 18x + 4y = 10 \quad \text{(Eq 3)} \]Now we have:
Eq 1: \( 3x – 4y = 11 \)
Eq 3: \( 18x + 4y = 10 \)
Since signs are different (\( -4y \) and \( +4y \)), we ADD the equations.
\[ (3x + 18x) + (-4y + 4y) = (11 + 10) \] \[ 21x = 21 \]Step 2: Solve for x
๐ก Divide
โ Working:
\[ x = 21 \div 21 = 1 \]Step 3: Solve for y
๐ก Substitute x back
Use Equation 2 (it looks simpler).
โ Working:
\[ 9(1) + 2y = 5 \] \[ 9 + 2y = 5 \] \[ 2y = 5 – 9 \] \[ 2y = -4 \] \[ y = -2 \]Final Answer:
\( x = 1, \quad y = -2 \)
โ (M1 for method to eliminate, M1 for substitution, A1 cao)