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GCSE Nov 2019 Edexcel Foundation Paper 1 (Non-Calculator)
Mark Scheme Legend
- M: Method mark (for a correct method or partial method)
- P: Process mark (for a correct process in problem solving)
- A: Accuracy mark (for a correct answer following correct working)
- B: Unconditional accuracy mark (no method needed)
- C: Communication mark (for clear statements)
- oe: Or equivalent
- cao: Correct answer only
- ft: Follow through
Table of Contents
- Question 1 (Place Value)
- Question 2 (Rounding)
- Question 3 (Multiplication)
- Question 4 (Simplifying Fractions)
- Question 5 (Percentage to Decimal)
- Question 6 (Pictograms)
- Question 7 (Time Calculations)
- Question 8 (Weights/Problem Solving)
- Question 9 (Angles on a Line)
- Question 10 (Coordinates)
- Question 11 (Probability Listing)
- Question 12 (Currency/Shopping)
- Question 13 (Algebra Simplification)
- Question 14 (Long Multiplication)
- Question 15 (Frequency Trees)
- Question 16 (Travel Graphs)
- Question 17 (Solving Equations)
- Question 18 (Pie Charts)
- Question 19 (Inequalities)
- Question 20 (LCM)
- Question 21 (Ratio)
- Question 22 (Fraction Multiplication)
- Question 23 (Construction)
- Question 24 (Angles in Triangles)
- Question 25 (Averages/Mean)
- Question 26 (Indices)
- Question 27 (Bearings/Scale)
- Question 28 (Angles at a Point)
- Question 29 (Congruence/Similarity)
Question 1 (1 mark)
Write down the value of the 7 in the number 1074
Worked Solution
Step 1: Understanding Place Value
What are we being asked to do?
We need to identify what the digit 7 represents based on its position in the number 1074.
✏ Working:
Let’s look at the columns:
Th H T U
1 0 7 4
^
Tens Column
What this tells us:
The 7 is in the Tens column. This means it represents 7 tens.
Final Answer:
70 (or 7 tens)
✓ (B1)
Question 2 (1 mark)
Write \( 4.58 \) correct to 1 decimal place.
Worked Solution
Step 1: Identifying the Rounding Digit
Why we do this:
We need to round to 1 decimal place, so we look at the digit in the first decimal place and the digit immediately to its right (the decider).
✏ Working:
Number: \( 4.58 \)
- 1st decimal place (rounding digit): 5
- 2nd decimal place (decider): 8
Step 2: Applying the Rounding Rule
How to round:
If the decider is 5 or greater, we round up. If it is less than 5, we stay the same.
✏ Working:
Since \( 8 \geq 5 \), we round the 5 up to 6.
\( 4.58 \rightarrow 4.6 \)
Final Answer:
4.6
✓ (B1)
Question 3 (1 mark)
Work out \( 31.7 \times 100 \)
Worked Solution
Step 1: Multiplying by Powers of 10
Why we do this:
Multiplying by 100 moves the decimal point two places to the right (or moves the digits two places to the left).
✏ Working:
\( 31.7 \times 10 = 317 \)
\( 31.7 \times 100 = 3170 \)
Moved decimal point: \( 31.7 \rightarrow 317. \rightarrow 3170. \)
Final Answer:
3170
✓ (B1)
Question 4 (1 mark)
Write the fraction \( \frac{28}{70} \) in its simplest form.
Worked Solution
Step 1: Identifying Common Factors
Why we do this:
To simplify a fraction, we divide both the numerator (top) and denominator (bottom) by their highest common factor.
✏ Working:
Both 28 and 70 are even, so let’s try dividing by 2:
\[ \frac{28 \div 2}{70 \div 2} = \frac{14}{35} \]Now, both 14 and 35 are in the 7 times table.
Step 2: Simplifying Further
How we do this:
Divide by 7 to reach the simplest form.
✏ Working:
\[ \frac{14 \div 7}{35 \div 7} = \frac{2}{5} \]Check: Can we divide 2 and 5 any further? No, they are prime numbers.
Final Answer:
\[ \frac{2}{5} \]
✓ (B1)
Question 5 (1 mark)
Write \( 15\% \) as a decimal.
Worked Solution
Step 1: Understanding Percentage
Why we do this:
“Percent” means “per 100”. To convert a percentage to a decimal, we divide by 100.
✏ Working:
\[ 15\% = \frac{15}{100} \]Step 2: Converting to Decimal
How we do this:
Dividing by 100 moves the decimal point two places to the left.
✏ Working:
\( 15 \div 100 = 0.15 \)
Final Answer:
0.15
✓ (B1)
Question 6 (4 marks total)
The pictogram shows information about the number of pictures sold in an art shop in each of January, February and March.
(a) Write down the number of pictures sold in January.
12 pictures were sold in April.
(b) Show this information on the pictogram.
(c) What was the total number of pictures sold in these four months?
Worked Solution
Part (a): Reading the Pictogram
Understanding the Key:
The key tells us that one full square \( \square \) represents 8 pictures.
✏ Working:
For January, there are 3 full squares.
\( 3 \times 8 = 24 \)
Answer (a): 24
Part (b): Drawing on the Pictogram
Why we do this:
We need to represent 12 pictures using squares where 1 square = 8 pictures.
✏ Working:
\( 12 \div 8 = 1.5 \)
We need 1 full square (8) and half a square (4).
\( 8 + 4 = 12 \)
Part (c): Calculating the Total
Strategy:
We need to calculate the value for each month and sum them up.
✏ Working:
January: \( 3 \times 8 = 24 \)
February: \( 3.5 \times 8 = 28 \) (or \( 3 \times 8 + 4 \))
March: \( 2.5 \times 8 = 20 \) (or \( 2 \times 8 + 4 \))
April: 12 (given)
Total:
24 28 20 + 12 ---- 84
Final Answer (c): 84
✓ (M1 A1)
Question 7 (2 marks)
Work out the difference, in minutes, between 1 hour 25 minutes and \( 1\frac{1}{4} \) hours.
Worked Solution
Step 1: Convert to Same Units
Why we do this:
We have one time in “hours and minutes” and another as a fraction of hours. It’s easiest to convert everything to minutes to find the difference.
✏ Working:
Time 1: 1 hour 25 minutes
\( 1 \text{ hour} = 60 \text{ minutes} \)
\( 60 + 25 = 85 \text{ minutes} \)
Time 2: \( 1\frac{1}{4} \) hours
\( \frac{1}{4} \text{ hour} = 60 \div 4 = 15 \text{ minutes} \)
So, 1 hour 15 minutes = \( 60 + 15 = 75 \text{ minutes} \)
Step 2: Calculate the Difference
What this tells us:
Now we simply subtract the smaller number of minutes from the larger.
✏ Working:
\[ 85 – 75 = 10 \]Final Answer:
10 minutes
✓ (M1 A1)
Question 8 (3 marks)
Prasha has five blocks of wood.
The total weight of all five blocks of wood is 3 kilograms.
4 of the blocks of wood each have a weight of 650 grams.
Work out the weight, in grams, of the other block of wood.
Worked Solution
Step 1: Unit Conversion
Why we do this:
The total is in kilograms, but the blocks are in grams. We need to work in the same units. The question asks for the answer in grams.
✏ Working:
\( 1 \text{ kg} = 1000 \text{ g} \)
\( 3 \text{ kg} = 3000 \text{ g} \)
Step 2: Calculate Weight of Known Blocks
Why we do this:
We know the weight of 4 blocks. Let’s find their total weight first.
✏ Working:
\( 4 \times 650 \)
650
x 4
-----
2600
2
\( 2600 \text{ g} \)
Step 3: Subtract to Find the Missing Block
What this tells us:
The remainder after subtracting the 4 known blocks from the total will be the weight of the 5th block.
✏ Working:
\( 3000 – 2600 \)
3000 - 2600 ------ 400
Final Answer:
400 grams
✓ (P1 P1 A1)
Question 9 (2 marks)
\( PQR \) is a straight line.
Work out the size of angle \( x \).
Worked Solution
Step 1: Angles on a Straight Line
Why we do this:
Angles on a straight line always add up to \( 180^\circ \).
✏ Working:
The total angle at point \( Q \) on the straight line \( PQR \) is \( 180^\circ \).
\[ x + 100 + 35 = 180 \]Step 2: Solve for x
How we do this:
Add the known angles and subtract from 180.
✏ Working:
\( 100 + 35 = 135 \)
\( x = 180 – 135 \)
\( x = 45 \)
Final Answer:
45°
✓ (M1 A1)
Question 10 (2 marks)
(a) Plot the point with coordinates \( (3, 2) \). Label this point \( A \).
(b) Write down the coordinates of the midpoint of \( BC \).
Worked Solution
Part (a): Plotting the Point
Strategy:
Coordinates are given as \( (x, y) \). We need to find \( x=3 \) on the horizontal axis and \( y=2 \) on the vertical axis.
✏ Working:
Go right 3 units from the origin.
Go up 2 units.
Mark the point with a cross or dot and label it \( A \).
Part (b): Finding the Midpoint
Method:
We can read it directly from the graph or calculate it using the midpoint formula: \( (\frac{x_1+x_2}{2}, \frac{y_1+y_2}{2}) \).
✏ Working:
Point \( B \) is at \( (-3, 2) \).
Point \( C \) is at \( (1, -2) \).
Midpoint \( x = \frac{-3 + 1}{2} = \frac{-2}{2} = -1 \)
Midpoint \( y = \frac{2 + (-2)}{2} = \frac{0}{2} = 0 \)
Answer (b): \( (-1, 0) \)
✓ (B1)
Question 11 (2 marks)
Mason throws a coin 3 times.
The outcome of each throw is either Heads or Tails.
List all the possible outcomes of the 3 throws.
Worked Solution
Step 1: Systematic Listing
Strategy:
We need to find all combinations of Heads (H) and Tails (T) for 3 throws. To ensure we don’t miss any, we can list them systematically.
Start with all Heads, then change the last one, then the middle one, etc.
✏ Working:
1. H H H
2. H H T
3. H T H
4. H T T
5. T H H
6. T H T
7. T T H
8. T T T
Check: Since there are 2 outcomes per throw and 3 throws, there should be \( 2 \times 2 \times 2 = 8 \) total outcomes.
Final Answer:
HHH, HHT, HTH, HTT, THH, THT, TTH, TTT
✓ (M1 A1)
Question 12 (5 marks total)
Rehan is on holiday in the USA.
He has $200 to spend on clothes.
Rehan buys
- 1 pair of trainers costing $60
- 3 T-shirts costing $25 each.
He also wants to buy a jacket costing $80
(a) Has Rehan got enough money to buy the jacket? You must show how you get your answer.
The trainers cost $60
The exchange rate is $1 = £0.749
Rehan says,
“The trainers cost less than £40”
Rehan is wrong.
(b) Using a suitable approximation, show working to explain why.
Worked Solution
Part (a): Calculating Costs
Step 1: Calculate total spent so far.
✏ Working:
Cost of trainers = $60
Cost of T-shirts = \( 3 \times \$25 = \$75 \)
Total spent = \( 60 + 75 = \$135 \)
Step 2: Calculate remaining money.
✏ Working:
Total budget = $200
Remaining = \( 200 – 135 = \$65 \)
Step 3: Compare with cost of jacket.
✏ Working:
Cost of jacket = $80
\( \$65 < \$80 \)
He does not have enough.
Answer (a): No (with working shown)
✓ (P1 P1 C1)
Part (b): Approximation
Why we do this:
We need to check if $60 is less than £40 using approximation. The exact rate is 0.749, which is close to 0.75 or \( \frac{3}{4} \).
✏ Working:
Approximate £0.749 as £0.75.
Convert $60 to £ using this approximation:
\[ 60 \times 0.75 = 60 \times \frac{3}{4} \] \[ 60 \div 4 = 15 \] \[ 15 \times 3 = 45 \]So $60 is approximately £45.
Since £45 > £40, Rehan is wrong.
Answer (b): Explanation using \( 60 \times 0.75 = 45 \)
✓ (P1 C1)
Question 13 (3 marks total)
(a) Simplify \( 2a \times 5b \)
(b) Simplify \( 3x + 2y + 5x – y \)
Worked Solution
Part (a): Multiplication in Algebra
Method:
Multiply the numbers first, then combine the letters.
✏ Working:
\( 2 \times 5 = 10 \)
\( a \times b = ab \)
Combine them: \( 10ab \)
Answer (a): \( 10ab \)
✓ (B1)
Part (b): Collecting Like Terms
Method:
Group the \( x \) terms together and the \( y \) terms together. Pay attention to the signs.
✏ Working:
\( x \) terms: \( 3x + 5x = 8x \)
\( y \) terms: \( 2y – y = 1y \) (or just \( y \))
Combine them: \( 8x + y \)
Answer (b): \( 8x + y \)
✓ (M1 A1)
Question 14 (2 marks)
Work out \( 23 \times 15 \)
Worked Solution
Step 1: Long Multiplication
Method:
We can use column multiplication. Multiply 23 by 5, then 23 by 10, then add.
✏ Working:
23 x 15 ----- 115 (23 x 5) 230 (23 x 10) ----- 345
Calculation details:
\( 5 \times 3 = 15 \) (put 5, carry 1)
\( 5 \times 2 = 10 \), plus 1 = 11. (115)
Place a 0 for the tens column.
\( 1 \times 3 = 3 \)
\( 1 \times 2 = 2 \). (230)
\( 115 + 230 = 345 \)
Final Answer:
345
✓ (M1 A1)
Question 15 (4 marks total)
120 people were at a hockey match.
Each person was asked if they wanted to stand or to sit to watch the match.
- 75 of the people were female
- 29 of the males wanted to stand
- 30 of the people wanted to sit
(a) Use this information to complete the frequency tree.
One of the 120 people is chosen at random.
(b) Write down the probability that this person is a male who wanted to stand.
Worked Solution
Part (a): Completing the Tree
Step 1: Fill in what we know directly.
Total = 120.
Females = 75.
Male Stand = 29.
Step 2: Calculate missing values.
Males: \( 120 – 75 (\text{female}) = 45 \text{ males} \)
Male Sit: \( 45 (\text{total male}) – 29 (\text{male stand}) = 16 \text{ male sit} \)
Total Sit: Question says “30 of the people wanted to sit”.
Female Sit: \( 30 (\text{total sit}) – 16 (\text{male sit}) = 14 \text{ female sit} \)
Female Stand: \( 75 (\text{total female}) – 14 (\text{female sit}) = 61 \text{ female stand} \)
Answer (a): Tree completed as shown (45, 16, 14, 61)
✓ (C1 C1 C1)
Part (b): Probability
Method:
Probability = (Number of desired outcomes) / (Total number of people).
✏ Working:
Males who want to stand = 29
Total people = 120
\[ P(\text{Male Stand}) = \frac{29}{120} \]Answer (b): \( \frac{29}{120} \)
✓ (B1)
Question 16 (3 marks total)
Steve drove from his home to his friend’s house.
He stayed at his friend’s house and then drove home.
Here is Steve’s travel graph.
(a) For how many minutes did Steve stay at his friend’s house?
(b) What was Steve’s average speed on his journey home?
Worked Solution
Part (a): Reading the Graph
What to look for:
The “stay” is represented by the horizontal section of the graph where the distance doesn’t change.
✏ Working:
The horizontal line starts at 12:45.
(It is exactly halfway between 12:30 and 13:00).
The horizontal line ends at 13:30.
Time difference:
12:45 to 13:00 = 15 minutes
13:00 to 13:30 = 30 minutes
\( 15 + 30 = 45 \text{ minutes} \)
Answer (a): 45 minutes
✓ (B1)
Part (b): Average Speed
Formula:
\( \text{Speed} = \frac{\text{Distance}}{\text{Time}} \)
✏ Working:
Distance: The return journey starts at 25 km and ends at 0 km. So he travels 25 km.
Time: The return journey starts at 13:30 and ends at 14:00.
\( 14:00 – 13:30 = 30 \text{ minutes} \).
To calculate speed in km/h, convert time to hours:
\( 30 \text{ minutes} = 0.5 \text{ hours} \).
Calculation:
\[ \text{Speed} = \frac{25}{0.5} \]Dividing by 0.5 is the same as multiplying by 2.
\[ 25 \times 2 = 50 \]Answer (b): 50 km/h
✓ (M1 A1)
Question 17 (3 marks)
\( x – 1 = 2 \)
Work out the value of \( 2x^2 \)
Worked Solution
Step 1: Solve for x
Why we do this:
We need to find the value of \( x \) first before we can calculate \( 2x^2 \).
✏ Working:
\( x – 1 = 2 \)
Add 1 to both sides:
\( x = 2 + 1 \)
\( x = 3 \)
Step 2: Substitute and Calculate
Order of Operations (BIDMAS):
We must do the Index (squared) before the Multiplication (times 2).
✏ Working:
Calculate \( x^2 \):
\( 3^2 = 3 \times 3 = 9 \)
Now multiply by 2:
\( 2 \times 9 = 18 \)
Final Answer:
18
✓ (P1 P1 A1)
Question 18 (4 marks)
The pie charts show information about the favourite animal of each student at school A and of each student at school B.
There are 480 students at school A. There are 760 students at school B.
Henry says,
“The same number of students at each school have tigers as their favourite animal.”
Is Henry correct? You must show how you get your answer.
Worked Solution
Step 1: Calculate Tigers at School A
Finding the angle:
The sum of angles in a pie chart is \( 360^\circ \).
In School A, we have monkeys (\( 60^\circ \)) and two sectors labelled \( x^\circ \) (lions and tigers).
✏ Working:
\( 2x + 60 = 360 \)
\( 2x = 300 \)
\( x = 150 \)
So, the angle for Tigers is \( 150^\circ \).
Finding the number of students:
✏ Working:
\[ \frac{150}{360} \times 480 \]Simplify fraction: \( \frac{15}{36} = \frac{5}{12} \)
\( \frac{5}{12} \times 480 \)
\( 480 \div 12 = 40 \)
\( 5 \times 40 = 200 \) students.
Step 2: Calculate Tigers at School B
Finding the angle:
The angle for tigers is marked with a right angle symbol, which means \( 90^\circ \).
✏ Working:
\[ \frac{90}{360} \times 760 \]\( \frac{90}{360} = \frac{1}{4} \)
\( \frac{1}{4} \text{ of } 760 = 760 \div 4 \)
190 4|760
So, 190 students.
Step 3: Compare and Conclude
Comparison:
School A: 200 students
School B: 190 students
Conclusion: No, Henry is incorrect. School A has 200 and School B has 190.
✓ (M1 M1 M1 C1)
Question 19 (2 marks)
Here is a number line.
Write down the inequality shown on the number line.
Worked Solution
Step 1: Interpreting the Circles
What the symbols mean:
- A filled (solid) circle means “included”. We use \( \le \) or \( \ge \).
- An empty (hollow) circle means “not included”. We use \( < \) or \( > \).
✏ Working:
At \( -3 \): Solid circle \( \rightarrow p \ge -3 \)
At \( 1 \): Hollow circle \( \rightarrow p < 1 \)
Final Answer:
\( -3 \le p < 1 \)
✓ (C2)
Question 20 (3 marks)
Find the Lowest Common Multiple (LCM) of 108 and 120.
Worked Solution
Step 1: Prime Factor Decomposition
Strategy:
Break both numbers down into their prime factors using a factor tree or division.
✏ Working:
For 108:
\( 108 = 2 \times 54 \)
\( 54 = 2 \times 27 \)
\( 27 = 3 \times 9 \)
\( 9 = 3 \times 3 \)
\( 108 = 2 \times 2 \times 3 \times 3 \times 3 = 2^2 \times 3^3 \)
For 120:
\( 120 = 10 \times 12 \)
\( 10 = 2 \times 5 \)
\( 12 = 3 \times 4 = 3 \times 2 \times 2 \)
\( 120 = 2 \times 2 \times 2 \times 3 \times 5 = 2^3 \times 3 \times 5 \)
Step 2: Construct the LCM
Method:
The LCM contains the highest power of each prime factor present in either number.
Alternatively, use a Venn diagram: Multiply the union of all factors.
✏ Working:
Primes involved: 2, 3, 5
Highest power of 2: \( 2^3 \) (from 120)
Highest power of 3: \( 3^3 \) (from 108)
Highest power of 5: \( 5^1 \) (from 120)
LCM = \( 2^3 \times 3^3 \times 5 \)
LCM = \( 8 \times 27 \times 5 \)
It is easier to do \( 8 \times 5 = 40 \) first.
\( 40 \times 27 \)
\( 4 \times 27 = 108 \)
\( 108 \times 10 = 1080 \)
Final Answer:
1080
✓ (M1 M1 A1)
Question 21 (4 marks)
There are 60 people in a choir.
Half of the people in the choir are women.
The number of women in the choir is 3 times the number of men in the choir.
The rest of the people in the choir are children.
the number of children in the choir : the number of men in the choir = \( n : 1 \)
Work out the value of \( n \).
You must show how you get your answer.
Worked Solution
Step 1: Calculate Number of Women
What we know: Total = 60. Half are women.
✏ Working:
\( \text{Women} = \frac{1}{2} \times 60 = 30 \)
Step 2: Calculate Number of Men
What we know: “The number of women… is 3 times the number of men.”
✏ Working:
\( \text{Women} = 3 \times \text{Men} \)
\( 30 = 3 \times \text{Men} \)
\( \text{Men} = 30 \div 3 = 10 \)
Step 3: Calculate Number of Children
What we know: The rest are children.
✏ Working:
\( \text{Total} = \text{Women} + \text{Men} + \text{Children} \)
\( 60 = 30 + 10 + \text{Children} \)
\( 60 = 40 + \text{Children} \)
\( \text{Children} = 60 – 40 = 20 \)
Step 4: Find the Ratio
Goal: Find ratio Children : Men in the form \( n : 1 \).
✏ Working:
Ratio = Children : Men
Ratio = \( 20 : 10 \)
Divide both sides by 10 to get 1 on the right:
\( 2 : 1 \)
So, \( n = 2 \).
Final Answer:
2
✓ (P1 P1 P1 A1)
Question 22 (3 marks)
Work out \( 1\frac{3}{4} \times 1\frac{1}{3} \)
Give your answer as a mixed number.
Worked Solution
Step 1: Convert to Improper Fractions
Why we do this:
It is much easier to multiply fractions than mixed numbers.
✏ Working:
\( 1\frac{3}{4} = \frac{1 \times 4 + 3}{4} = \frac{7}{4} \)
\( 1\frac{1}{3} = \frac{1 \times 3 + 1}{3} = \frac{4}{3} \)
Step 2: Multiply
Method:
Multiply numerators together and denominators together.
✏ Working:
\[ \frac{7}{4} \times \frac{4}{3} = \frac{7 \times 4}{4 \times 3} = \frac{28}{12} \]Alternatively, cancel the 4s before multiplying:
\[ \frac{7}{\cancel{4}^1} \times \frac{\cancel{4}^1}{3} = \frac{7}{3} \]Step 3: Convert back to Mixed Number
Why we do this:
The question asks for the answer as a mixed number.
✏ Working:
\( \frac{7}{3} \) means \( 7 \div 3 \).
\( 7 \div 3 = 2 \) remainder \( 1 \).
So, \( 2\frac{1}{3} \).
Final Answer:
\( 2\frac{1}{3} \)
✓ (M1 M1 A1)
Question 23 (2 marks)
Use a ruler and compasses to construct the line from the point \( P \) perpendicular to the line \( CD \).
You must show all construction lines.
Worked Solution
Step 1: Construction Method
Instructions:
- Place the compass point on \( P \).
- Draw an arc that crosses the line \( CD \) at two points (let’s call them A and B).
- Keep the compass width the same (or change it to be more than half the distance AB).
- Place the compass point on A and draw an arc below the line.
- Place the compass point on B and draw an arc to intersect the previous one.
- Draw a straight line from \( P \) through the intersection of the arcs.
Answer: Correct construction showing arcs intersecting the line and crossing arcs below (or above/below) the line.
✓ (C2)
Question 24 (4 marks)
The diagram shows triangle \( ABC \).
\( ADB \) is a straight line.
the size of angle \( DCB \) : the size of angle \( ACD = 2 : 1 \)
Work out the size of angle \( BDC \).
Worked Solution
Step 1: Calculate Angle ACB
Why we do this:
We know two angles in the large triangle \( ABC \). We can calculate the third angle because angles in a triangle sum to \( 180^\circ \).
✏ Working:
\( \angle A = 75^\circ \)
\( \angle B = 51^\circ \)
\( \angle ACB = 180 – (75 + 51) \)
\( 75 + 51 = 126 \)
\( 180 – 126 = 54^\circ \)
Step 2: Use the Ratio
What we know:
\( \angle DCB : \angle ACD = 2 : 1 \)
Total parts = \( 2 + 1 = 3 \).
The total angle \( ACB \) is \( 54^\circ \).
✏ Working:
Value of one part = \( 54 \div 3 = 18^\circ \).
\( \angle ACD = 1 \text{ part} = 18^\circ \).
\( \angle DCB = 2 \text{ parts} = 36^\circ \).
Step 3: Calculate Angle BDC
Method:
We can focus on triangle \( ACD \). The exterior angle of a triangle is equal to the sum of the two opposite interior angles. Angle \( BDC \) is exterior to triangle \( ACD \).
Alternatively, use the angles in triangle \( BCD \).
✏ Working (Method 1 – Exterior Angle):
\( \angle BDC = \angle A + \angle ACD \)
\( \angle BDC = 75 + 18 = 93^\circ \)
✏ Working (Method 2 – Triangle BCD):
In triangle \( BCD \):
\( \angle B = 51^\circ \)
\( \angle DCB = 36^\circ \)
\( \angle BDC = 180 – (51 + 36) \)
\( 51 + 36 = 87 \)
\( 180 – 87 = 93^\circ \)
Final Answer:
93°
✓ (M1 M1 M1 A1)
Question 25 (3 marks)
4 red bricks have a mean weight of 5 kg.
5 blue bricks have a mean weight of 9 kg.
1 green brick has a weight of 6 kg.
Donna says,
“The mean weight of the 10 bricks is less than 7kg.”
Is Donna correct?
You must show how you get your answer.
Worked Solution
Step 1: Calculate Total Weight
Why we do this:
To find the mean of all bricks, we first need the total weight of all bricks.
\( \text{Total Weight} = \text{Count} \times \text{Mean} \)
✏ Working:
Red: \( 4 \times 5 = 20 \text{ kg} \)
Blue: \( 5 \times 9 = 45 \text{ kg} \)
Green: \( 1 \times 6 = 6 \text{ kg} \)
Grand Total: \( 20 + 45 + 6 \)
\( 20 + 45 = 65 \)
\( 65 + 6 = 71 \text{ kg} \)
Step 2: Calculate Combined Mean
Method:
Divide the total weight by the total number of bricks (10).
✏ Working:
\[ \text{Mean} = \frac{71}{10} = 7.1 \text{ kg} \]Step 3: Conclusion
Compare:
Donna thinks it is less than 7kg.
The actual mean is 7.1kg.
Answer: No, Donna is incorrect. The mean is 7.1 kg which is greater than 7 kg.
✓ (P1 P1 C1)
Question 26 (3 marks total)
(a) Simplify \( (p^2)^5 \)
(b) Simplify \( 12x^7y^3 \div 6x^3y \)
Worked Solution
Part (a): Power of a Power
Rule:
When raising a power to another power, you multiply the indices: \( (a^m)^n = a^{m \times n} \).
✏ Working:
\( 2 \times 5 = 10 \)
So, \( p^{10} \)
Answer (a): \( p^{10} \)
✓ (B1)
Part (b): Division with Indices
Method:
Divide the numbers, and subtract the powers for the letters.
Remember that \( y \) is the same as \( y^1 \).
✏ Working:
Numbers: \( 12 \div 6 = 2 \)
x terms: \( x^7 \div x^3 = x^{7-3} = x^4 \)
y terms: \( y^3 \div y^1 = y^{3-1} = y^2 \)
Combine them: \( 2x^4y^2 \)
Answer (b): \( 2x^4y^2 \)
✓ (M1 A1)
Question 27 (5 marks total)
The accurate scale drawing shows the positions of port \( P \) and a lighthouse \( L \).
Scale: 1 cm represents 4 km.
Aleena sails her boat from port \( P \) on a bearing of \( 070^\circ \).
She sails for \( 1\frac{1}{2} \) hours at an average speed of 12 km/h to a port \( Q \).
Find:
(i) the distance, in km, of port \( Q \) from lighthouse \( L \),
(ii) the bearing of port \( Q \) from lighthouse \( L \).
Worked Solution
Step 1: Calculate Distance to Q
Formula: \( \text{Distance} = \text{Speed} \times \text{Time} \)
✏ Working:
Speed = 12 km/h
Time = \( 1\frac{1}{2} \) hours = 1.5 hours
\( \text{Distance PQ} = 12 \times 1.5 = 18 \text{ km} \)
Step 2: Convert to Scale
Scale: 1 cm represents 4 km.
✏ Working:
\( 18 \div 4 = 4.5 \text{ cm} \)
So, we need to draw a line 4.5 cm long from P.
Step 3: Plot Point Q
Construction:
- Place a protractor at P, aligned with the North line.
- Mark \( 070^\circ \) (clockwise from North).
- Draw a straight line through this mark.
- Measure 4.5 cm along this line and mark point Q.
Step 4: Measure QL
Measurement:
Now measure the distance from the new point Q to the lighthouse L using a ruler.
Then convert back to real kilometers (\( \text{cm} \times 4 \)).
Then measure the bearing from L (North line at L clockwise to line LQ).
✏ Expected Results (from Mark Scheme):
Distance QL: Approx 5.2 – 5.7 cm on paper \( \rightarrow \) 20 – 23 km.
Bearing of Q from L: Angle is around 317° – 330°.
Answer (i): Distance in range 20 km – 23 km
Answer (ii): Bearing in range 317° – 330°
✓ (Total 5 marks)
Question 28 (3 marks)
The diagram shows triangle \( AOB \).
Angle \( AOB \) is not an obtuse angle.
Find the greatest value of \( x \).
You must show all your working.
Worked Solution
Step 1: Set up the Expression
What is angle AOB?
It is the sum of the three smaller angles at O.
✏ Working:
\( \text{Angle } AOB = 2x + 3x + 10 \)
\( = 5x + 10 \)
Step 2: Apply the Condition
What does “not obtuse” mean?
An obtuse angle is between \( 90^\circ \) and \( 180^\circ \).
Since this is an angle in a triangle, it must be less than \( 180^\circ \).
If it is not obtuse, it must be \( 90^\circ \) or less (Acute or Right).
✏ Working:
\( 5x + 10 \leq 90 \)
Step 3: Solve for x
Solve the inequality:
✏ Working:
\( 5x \leq 90 – 10 \)
\( 5x \leq 80 \)
\( x \leq 80 \div 5 \)
\( x \leq 16 \)
Greatest value: 16
✓ (P1 P1 A1)
Question 29 (4 marks total)
\( ABC \) and \( PQR \) are similar right-angled triangles.
angle \( ABC \) = angle \( PQR \)
(a) Work out the length of \( PR \).
Triangle \( EGH \) is congruent to triangle \( KGF \).
\( HK = 10 \text{ cm} \).
\( HG = 4 \text{ cm} \).
(b) Work out the length of \( EF \).
Worked Solution
Part (a): Similar Triangles
Strategy: Find the scale factor between the corresponding sides.
Side \( BC = 15 \) corresponds to side \( RQ = 10 \).
✏ Working:
Scale factor \( = \frac{10}{15} = \frac{2}{3} \)
We need to find \( PR \), which corresponds to \( AC = 9 \).
\( PR = 9 \times \frac{2}{3} \)
\( PR = \frac{18}{3} = 6 \text{ cm} \)
Answer (a): 6 cm
✓ (M1 A1)
Part (b): Congruent Triangles
Understanding Congruence:
Triangles \( EGH \) and \( KGF \) are identical in size and shape.
We need to match the corresponding sides:
- \( HG = 4 \) corresponds to \( FG \). So \( FG = 4 \).
- \( EG \) corresponds to \( KG \).
✏ Working:
First, find \( KG \):
\( HK = HG + GK \)
\( 10 = 4 + GK \implies GK = 6 \text{ cm} \).
Since \( EG = KG \), then \( EG = 6 \text{ cm} \).
The diagram shows \( E, F, G \) are on the same vertical line.
\( EF = EG – FG \)
\( EF = 6 – 4 = 2 \text{ cm} \).
Answer (b): 2 cm
✓ (P1 A1)