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Pearson Edexcel GCSE Summer 2022 Foundation Paper 3
๐ How to Use This Page
- Try it first: Attempt each question before looking at the solution.
- Show Solution: Click the green button to reveal step-by-step working.
- Calculator Allowed: This is Paper 3, so you may use a calculator.
- Navigation: Use the links below to jump to specific questions.
๐ Table of Contents
- Question 1 (Percentages to Fractions)
- Question 2 (Fraction of an Amount)
- Question 3 (Factors)
- Question 4 (Algebraic Simplification)
- Question 5 (Square Roots)
- Question 6 (Quadrilateral Symmetry)
- Question 7 (Data Tables)
- Question 8 (Number Sequences)
- Question 9 (3D Shapes Properties)
- Question 10 (Probability Scale)
- Question 11 (Problem Solving)
- Question 12 (Fractions)
- Question 13 (Bearings & Distances)
- Question 14 (Averages & Range)
- Question 15 (Calculator Use)
- Question 16 (Area & Triangles)
- Question 17 (Algebra: Expand & Solve)
- Question 18 (Rounding & Sig Figs)
- Question 19 (Percentages)
- Question 20 (Angles in Polygons)
- Question 21 (LCM)
- Question 22 (Pythagoras)
- Question 23 (Substitution)
- Question 24 (Ratio & Algebra)
- Question 25 (Best Buy)
- Question 26 (Frequency Polygons)
- Question 27 (Speed, Distance, Time)
- Question 28 (Area & Algebra)
- Question 29 (Unit Conversion)
- Question 30 (Reverse Percentages)
Question 1 (1 mark)
Write \( 35\% \) as a fraction.
๐ Worked Solution
Step 1: Understanding percentages
๐ก Why we do this: The symbol \( \% \) means “per cent” or “out of 100”. To convert a percentage to a fraction, we just write the number over 100.
โ๏ธ Working:
\[ 35\% = \frac{35}{100} \]Step 2: Simplifying the fraction
๐ก What’s next: Both numbers end in 0 or 5, so they can be divided by 5.
๐ฉ Calculator Method: Type 35, press the fraction key a b/c or โป/โป, type 100, then press =.
Final Answer:
\[ \frac{7}{20} \] (or \( \frac{35}{100} \))
โ (1)
Question 2 (1 mark)
Work out \( \frac{1}{4} \) of 28
๐ Worked Solution
Step 1: Interpreting the question
๐ก Strategy: Finding “one quarter of” a number is the same as dividing that number by 4.
The word “of” in maths usually means multiply: \( \frac{1}{4} \times 28 \).
Step 2: Calculation
We know that \( 4 \times 7 = 28 \), so:
\[ 28 \div 4 = 7 \]Final Answer:
7
โ (1)
Question 3 (1 mark)
Write down two factors of 12
๐ Worked Solution
Step 1: Understanding ‘Factors’
๐ก Definition: Factors are whole numbers that divide into a number exactly (without leaving a remainder).
We need to find numbers that 12 can be divided by.
Step 2: Listing the factors
Let’s find the factor pairs of 12:
- \( 1 \times 12 = 12 \) (so 1 and 12 are factors)
- \( 2 \times 6 = 12 \) (so 2 and 6 are factors)
- \( 3 \times 4 = 12 \) (so 3 and 4 are factors)
The full list of factors is: 1, 2, 3, 4, 6, 12
Final Answer:
Any two from: 1, 2, 3, 4, 6, 12
โ (1)
Question 4 (1 mark)
Simplify \( 2m \times 3 \)
๐ Worked Solution
Step 1: Understanding algebra rules
๐ก Strategy: When multiplying algebraic terms, we multiply the numbers (coefficients) together and keep the letters (variables).
Step 2: Simplify
So,
\[ 6 \times m = 6m \]Final Answer:
\( 6m \)
โ (1)
Question 5 (1 mark)
Find \( \sqrt{1.69} \)
๐ Worked Solution
Step 1: Using the calculator
๐ก Tool: This is a square root symbol. It asks: “What number multiplied by itself gives 1.69?”
๐ฉ Calculator Steps:
- Press the square root button:
\( \sqrt{\square} \) - Type:
1.69 - Press:
=
Step 2: Checking the answer
The calculator shows: 1.3
Check: \( 1.3 \times 1.3 = 1.69 \)
Final Answer:
1.3
โ (1)
Question 6 (2 marks)
On the grid, draw a quadrilateral with
- no lines of symmetry
- and rotational symmetry of order 2
๐ Worked Solution
Step 1: Understanding the requirements
We need a four-sided shape (quadrilateral) with two specific properties:
- No lines of symmetry: If you fold it in half, the two halves won’t match.
- Rotational symmetry of order 2: If you spin it 360ยฐ, it looks the same in 2 positions (start and halfway/180ยฐ).
Step 2: Identifying the shape
Which quadrilaterals have rotational symmetry of order 2?
- Rectangle (has lines of symmetry โ)
- Rhombus (has lines of symmetry โ)
- Parallelogram (has NO lines of symmetry โ , order 2 โ )
So, we must draw a parallelogram (that isn’t a rectangle or rhombus).
Step 3: Drawing the shape
To draw a parallelogram:
- Draw a base line (e.g., 4 squares long).
- Draw a top line of the same length, but shifted to the side (e.g., 2 squares right).
- Connect the ends.
Final Answer:
A parallelogram (that is not a rectangle or rhombus) is drawn on the grid.
โโ (2)
Question 7 (3 marks)
The table shows the total number of apples sold and the total number of oranges sold in a shop in each of three weeks.
In total for the three weeks, more apples than oranges were sold.
How many more?
๐ Worked Solution
Step 1: Calculate total apples
๐ก Strategy: Add up the number of apples for all three weeks.
Total apples = 253
Step 2: Calculate total oranges
๐ก Strategy: Add up the number of oranges for all three weeks.
Total oranges = 224
Step 3: Find the difference
๐ก Strategy: Subtract the total oranges from the total apples to find “how many more”.
Final Answer:
29
โโโ (3)
Question 8 (2 marks)
Here are the first five terms of a number sequence.
3 8 13 18 23
(a) Write down the next two terms of this sequence.
Jim says that 50 is a term in this sequence.
Jim is wrong.
(b) Explain why.
๐ Worked Solution
Part (a): Next two terms
๐ก Finding the rule: Look at the gap between the numbers.
\( 8 – 3 = 5 \)
\( 13 – 8 = 5 \)
The rule is add 5 each time.
Next term: \( 23 + 5 = 28 \)
Term after that: \( 28 + 5 = 33 \)
Part (b): Explain why 50 is not in the sequence
๐ก Strategy: Look at the properties of the numbers in the sequence (3, 8, 13, 18, 23, 28, 33…).
Notice a pattern in the last digit (units digit).
Reason:
- All terms in the sequence end in either 3 or 8.
- The number 50 ends in 0, so it cannot be in the sequence.
Alternative reason: If we continue the sequence: …, 33, 38, 43, 48, 53… We can see that we skip 50.
Final Answer:
(a) 28, 33
(b) All terms end in 3 or 8 (or 50 does not end in 3 or 8)
โโ (2)
Question 9 (2 marks)
The diagram shows a solid triangular prism.
(a) Write down the number of faces of the prism.
(b) Write down the number of edges of the prism.
๐ Worked Solution
Part (a): Faces
๐ก Definition: A face is a flat surface of the 3D shape.
- 2 triangular faces (front and back)
- 3 rectangular faces (bottom and two sides)
Part (b): Edges
๐ก Definition: An edge is a line where two faces meet.
- 3 edges on the front triangle
- 3 edges on the back triangle
- 3 edges connecting the front to the back
Final Answer:
(a) 5
(b) 9
โโ (2)
Question 10 (4 marks)
Here is a list of 8 numbers.
2 2 3 5 6 6 8 9
Kim picks at random one of these numbers.
(a) On the probability scale below, mark with a cross (ร) the probability that Kim picks a number 7.
(b) On the probability scale below, mark with a cross (ร) the probability that Kim picks a number greater than 5.
(c) Find the probability that Kim picks an even number.
๐ Worked Solution
Part (a): Probability of picking 7
๐ก Check list: Look at the list: 2, 2, 3, 5, 6, 6, 8, 9.
Is the number 7 in the list? No.
This means the probability is 0 (impossible).
Mark a cross at 0.
Part (b): Probability of > 5
๐ก Count: Count numbers strictly greater than 5.
List: 2, 2, 3, 5, 6, 6, 8, 9
There are 4 numbers greater than 5.
Total numbers = 8.
Probability = \( \frac{4}{8} = \frac{1}{2} \)
Mark a cross at \( \frac{1}{2} \).
Part (c): Probability of even number
๐ก Identify even numbers: Numbers divisible by 2.
List: 2, 2, 3, 5, 6, 6, 8, 9
The even numbers are: 2, 2, 6, 6, 8.
Count of even numbers = 5
Total numbers = 8
Probability = \( \frac{5}{8} \)
Final Answer:
(a) Cross at 0
(b) Cross at \( \frac{1}{2} \)
(c) \( \frac{5}{8} \)
โโโโ (4)
Question 11 (3 marks)
Sinita wants to make 35 picture frames.
She needs 4 nails for each frame.
Sinita has 3 boxes of nails.
There are 48 nails in each box.
Has Sinita got enough nails to make all 35 frames?
Show how you get your answer.
๐ Worked Solution
Step 1: Calculate nails needed
๐ก Goal: Find out how many nails she needs in total.
She needs 4 nails for each of the 35 frames.
Nails needed: 140
Step 2: Calculate nails available
๐ก Goal: Find out how many nails she actually has.
She has 3 boxes, with 48 nails in each.
Nails available: 144
Step 3: Compare and Conclude
๐ก Comparison: Is the number she has (144) greater than or equal to the number she needs (140)?
144 is greater than 140.
\( 144 > 140 \)
She has 4 nails left over.
Final Answer:
Yes, she has enough nails (144 > 140).
โโโ (3)
Question 12 (2 marks)
Write 60 metres as a fraction of 1000 metres.
Give your answer in its simplest form.
๐ Worked Solution
Step 1: Write as a fraction
๐ก Meaning: “A as a fraction of B” means \( \frac{A}{B} \).
Step 2: Simplify the fraction
๐ก Method: Divide top and bottom by the same number until you can’t go any further.
Divide by 10 (remove zeros):
\[ \frac{6}{100} \]Divide by 2:
\[ \frac{3}{50} \]This cannot be simplified further.
๐ฉ Calculator Check: Type 60 / 1000 or use the fraction button, press =.
Final Answer:
\[ \frac{3}{50} \]
โโ (2)
Question 13 (4 marks)
The accurately drawn map shows the positions of three points, A, B and C, in a field.
Scale: 1 cm represents 150 metres
Parveen walks in a straight line from A to B.
She then walks in a straight line from B to C.
Susan walks in a straight line from A to C.
Parveen walks more metres than Susan.
(a) How many more?
(b) Find by measurement the bearing of A from C.
๐ Worked Solution
Part (a): Measuring distances
๐ก Instructions: Use a ruler to measure the lines on the original exam paper.
Note: Values depend on exact printing size, but standard exam values are usually:
- Length AB โ 5 cm
- Length BC โ 4 cm
- Length AC โ 7 cm
Parveen’s Distance: A to B + B to C
\( 5 \text{ cm} + 4 \text{ cm} = 9 \text{ cm} \)
Susan’s Distance: A to C
\( 7 \text{ cm} \)
Difference in cm:
\( 9 – 7 = 2 \text{ cm} \)
Part (a): Converting scale
๐ก Scale: 1 cm represents 150 metres.
(Acceptable range usually allows for small measurement errors, e.g., 210-390m)
Part (b): Measuring bearing
๐ก Definition: A bearing is an angle measured clockwise from North.
“Bearing of A from C” means start at C, face North, and turn clockwise until you face A.
1. Place protractor on C, with 0ยฐ on the North line.
2. Measure clockwise to the line CA.
The angle is large (reflex), so it’s easier to measure the small angle inside (North to CA anticlockwise) and subtract from 360ยฐ, OR measure the obtuse angle from North clockwise.
Looking at the diagram, A is North-West of C.
The angle is approximately 288ยฐ.
(Acceptable range: 286ยฐ to 290ยฐ)
Final Answer:
(a) 300 metres (range 210-390 allowed)
(b) 288ยฐ (range 286-290 allowed)
โโโโ (4)
Question 14 (4 marks)
Here is the shoe size of each of 12 boys in a class.
4 5 6 6 6 7 7 8 8 8 8 9
(a) Find the median.
(b) Work out the range.
For the shoe sizes of each of 12 girls in the class,
- the median size is 6
- the range is 3
(c) Compare the distribution of the shoe sizes of the boys with the distribution of the shoe sizes of the girls.
๐ Worked Solution
Part (a): Median
๐ก Definition: The median is the middle number when the data is ordered.
There are 12 numbers (even amount), so the median is halfway between the 6th and 7th numbers.
4, 5, 6, 6, 6, 7, 7, 8, 8, 8, 8, 9
The 6th number is 7.
The 7th number is 7.
Halfway between 7 and 7 is 7.
Part (b): Range
๐ก Definition: Range = Biggest value – Smallest value.
Biggest = 9
Smallest = 4
\[ 9 – 4 = 5 \]Part (c): Comparison
๐ก Strategy: To compare distributions, you must mention:
- An average (median or mean) to compare the “typical” value.
- A measure of spread (range) to compare consistency/variety.
1. Compare Medians:
Boys’ median (7) is greater than Girls’ median (6).
Interpretation: On average, boys have larger feet.
2. Compare Ranges:
Boys’ range (5) is greater than Girls’ range (3).
Interpretation: Boys’ shoe sizes are more spread out (or girls’ sizes are more consistent).
Final Answer:
(a) 7
(b) 5
(c) The boys have a higher median shoe size (7 vs 6). The boys have a larger range of shoe sizes (5 vs 3).
โโโโ (4)
Question 15 (2 marks)
Work out \( \frac{2.75 \times 14.6}{10 – 1.97} \)
๐ Worked Solution
Step 1: Calculate the top (numerator)
๐ฉ Calculator: Type 2.75 ร 14.6 =
Step 2: Calculate the bottom (denominator)
๐ฉ Calculator: Type 10 - 1.97 =
Step 3: Division
๐ฉ Calculator: 40.15 รท 8.03 =
Answer: 5
Tip: On a modern calculator, use the fraction button โป/โป and type it exactly as seen.
Final Answer:
5
โโ (2)
Question 16 (2 marks)
On the centimetre grid, draw an isosceles triangle with an area of 12 cmยฒ.
๐ Worked Solution
Step 1: Formula for Area of a Triangle
๐ก Formula: \( \text{Area} = \frac{\text{base} \times \text{height}}{2} \)
We need the area to be 12.
\[ 12 = \frac{\text{base} \times \text{height}}{2} \]Multiply both sides by 2:
\[ 24 = \text{base} \times \text{height} \]So, we need a base and height that multiply to give 24.
Step 2: Choose dimensions
Possible pairs for 24:
- \( 4 \times 6 \)
- \( 6 \times 4 \)
- \( 8 \times 3 \)
Since it must be an isosceles triangle (two sides equal), it’s easiest to pick an even number for the base, so we can put the peak exactly in the middle.
Let’s use Base = 6 cm and Height = 4 cm.
Step 3: Draw the triangle
- Draw the base line of 6 cm (6 squares).
- Find the midpoint (3 cm from the end).
- Go up 4 cm (4 squares) from the midpoint to mark the top vertex.
- Connect the top vertex to the ends of the base.
Final Answer:
An isosceles triangle with base 6cm and height 4cm (or base 4cm/height 6cm, or base 8cm/height 3cm) is drawn.
โโ (2)
Question 17 (4 marks)
(a) Expand \( 3(4 – 2x) \)
(b) Solve \( \frac{3y}{4} = 12 \)
(c) Factorise \( 4p + 6 \)
๐ Worked Solution
Part (a): Expand
๐ก Method: Multiply the number outside the bracket by each term inside.
Combine them:
\[ 12 – 6x \]Part (b): Solve
๐ก Method: Rearrange to get \( y \) on its own.
Equation: \( \frac{3y}{4} = 12 \)
1. Multiply both sides by 4 to remove the fraction:
\[ 3y = 12 \times 4 \] \[ 3y = 48 \]2. Divide both sides by 3:
\[ y = \frac{48}{3} \] \[ y = 16 \]Part (c): Factorise
๐ก Method: Put the expression back into brackets by finding the highest common factor (HCF).
Expression: \( 4p + 6 \)
What number divides into both 4 and 6?
Answer: 2
Divide each term by 2:
\[ 4p \div 2 = 2p \] \[ 6 \div 2 = 3 \]Put the 2 outside the bracket:
\[ 2(2p + 3) \]Final Answer:
(a) \( 12 – 6x \)
(b) \( y = 16 \)
(c) \( 2(2p + 3) \)
โโโโ (4)
Question 18 (2 marks)
(a) Write 2530 correct to 2 significant figures.
(b) Write 0.0874 correct to 1 significant figure.
๐ Worked Solution
Part (a): 2 Significant Figures
๐ก Method: Count the first two non-zero digits from the left.
Number: 2 5 3 0
The 2nd sig fig is 5. The next digit is 3.
Since 3 is less than 5, we round down (keep the 5 as it is).
Replace remaining digits with zeros to keep the value correct.
25 | 30
Becomes: 2500
Part (b): 1 Significant Figure
๐ก Method: Zeros at the start don’t count. Find the first non-zero digit.
Number: 0.0 8 7 4
The 1st sig fig is 8. The next digit is 7.
Since 7 is 5 or more, we round up (change 8 to 9).
0.08 | 74
Becomes: 0.09
Final Answer:
(a) 2500
(b) 0.09
โโ (2)
Question 19 (4 marks)
There are 400 counters in a box.
The counters are red or yellow or green.
- \( \frac{3}{8} \) of the counters are red.
- 82 of the counters are yellow.
What percentage of the counters are green?
๐ Worked Solution
Step 1: Calculate number of Red counters
๐ก Method: Find \( \frac{3}{8} \) of 400.
\( (400 \div 8) \times 3 \)
\( 400 \div 8 = 50 \)
\( 50 \times 3 = 150 \)
Red counters = 150
Step 2: Calculate number of Green counters
๐ก Method: Subtract red and yellow from the total.
Red = 150
Yellow = 82
Total = 400
Red + Yellow = \( 150 + 82 = 232 \)
Green = \( 400 – 232 = 168 \)
Step 3: Convert Green to Percentage
๐ก Method: \( \frac{\text{Part}}{\text{Total}} \times 100 \)
๐ฉ Calculator: 168 รท 400 ร 100 =
42%
Check: \( \frac{168}{400} = \frac{42}{100} = 42\% \)
Final Answer:
42%
โโโโ (4)
Question 20 (5 marks)
In the diagram, \( PQR \) is an isosceles triangle with \( PQ = PR \).
\( APR \) and \( CQD \) are parallel lines.
\( BPQ \) is a straight line.
Angle \( APB = 56^\circ \)
Work out the size of angle \( CQR \).
Give a reason for each stage of your working.
๐ Worked Solution
Step 1: Find angle \( QPR \)
๐ก Reason: Vertically opposite angles are equal.
Angle \( APB \) and Angle \( QPR \) are vertically opposite (where two straight lines cross).
(Vertically opposite angles are equal)
Step 2: Find angles inside Triangle \( PQR \)
๐ก Reason: Base angles of an isosceles triangle are equal.
Triangle \( PQR \) is isosceles (\( PQ = PR \)), so \( \angle PQR = \angle PRQ \).
Angles in a triangle add to 180ยฐ.
So, \( \angle PQR = 62^\circ \) (and \( \angle PRQ = 62^\circ \))
Step 3: Find angle \( CQR \)
๐ก Reason: Alternate angles are equal (Z-angles) OR Allied angles (C-angles).
Method 1 (Alternate): Angle \( CQP \) and Angle \( QPR \) are alternate angles because lines \( APR \) and \( CQD \) are parallel. But wait, \( APR \) is a line, not just \( AP \). Let’s check the lines again.
Actually, let’s use Allied (Co-interior) angles or Corresponding angles depending on the parallel lines.
Lines \( APR \) and \( CQD \) are parallel. Line \( PQR \) is a transversal? No, \( PQ \) is part of the line \( BPQ \).
Let’s look at the parallel lines \( APR \) and \( CQD \).
Line \( PR \) acts as a transversal connecting parallel lines \( AR \) and \( CD \)? No.
Let’s use Alternate angles with parallel lines \( AR \) and \( CD \) and transversal \( PR \). This gives \( \angle PRQ = \angle DQR \)? No.
Let’s look at the diagram simpler:
- \( \angle CQP \) and \( \angle APQ \) are Allied (add to 180)? No, \( P \) and \( Q \) are on the transversal.
- Actually, \( \angle CQP \) corresponds to \( \angle APB \)? No.
- \( \angle CQP \) is alternate to \( \angle QPA \)? Yes!
\( \angle APQ \) is on a straight line with \( 56^\circ \)? No, \( BPQ \) is straight. \( A \) is on a parallel line.
Wait, let’s look at the parallel line relation:
Parallel lines: \( APR \) and \( CQD \).
Transversal: \( BPQ \).
Therefore, \( \angle CQP \) = \( \angle APB \) (Corresponding angles)? No, \( A \) and \( C \) are on the same side?
Let’s use Corresponding angles: \( \angle DQP = \angle RPV \)? No.
Correct Parallel Line Rule:
\( \angle CQP \) and \( \angle APQ \) are Alternate? No.
Let’s look at \( \angle CQP \) and \( \angle QPR \).
Actually, \( \angle CQP \) corresponds to \( \angle APB \) ?? No.
Let’s use Alternate Angles (Z-angles):
The “Z” shape is formed by \( A-P-Q-D \). So \( \angle APQ = \angle PQD \).
Is \( \angle APQ \) known? Angles on a straight line at P? We know \( \angle APB = 56 \). \( \angle BPQ \) is a line. So \( \angle APQ = 180 – 56 = 124 \).
So \( \angle PQD = 124 \).
Then \( \angle CQP \) is vertically opposite \( \angle PQD \)? No.
Alternative Strategy:
\( \angle CQP \) corresponds to \( \angle APB \) IF \( AP \) and \( CQ \) are parallel.
Lines are \( APR \) and \( CQD \). So \( AP \) is parallel to \( CQ \).
Transversal is \( BPQ \).
\( \angle CQP \) and \( \angle APB \) are Corresponding Angles (F-angles). Wait, they are on the same side of the transversal and in corresponding positions.
Wait, if \( AP \) is parallel to \( CQ \), then \( \angle CQP = \angle APQ \) (Alternate)? No.
Actually, \( \angle APB \) (56) and \( \angle CQP \) are Corresponding Angles.
So \( \angle CQP = 56^\circ \).
\( \angle CQP = 56^\circ \) (Corresponding angles are equal)
Step 4: Final Addition
We need angle \( CQR \).
\( \angle CQR = \angle CQP + \angle PQR \)
\( \angle CQR = 56^\circ + 62^\circ \)
\( \angle CQR = 118^\circ \)
Final Answer:
118ยฐ
โโโโโ (5)
Question 21 (2 marks)
Work out the lowest common multiple (LCM) of 24 and 56
๐ Worked Solution
Step 1: List Multiples Method
๐ก Method: Write out the times tables for both numbers until you find the first match.
Multiples of 56: 56, 112, 168, 224, …
Multiples of 24: 24, 48, 72, 96, 120, 144, 168, …
The first number in both lists is 168.
Alternative Method: Prime Factors
24 = \( 2 \times 2 \times 2 \times 3 \) = \( 2^3 \times 3 \)
56 = \( 2 \times 2 \times 2 \times 7 \) = \( 2^3 \times 7 \)
LCM = Take highest power of each prime:
\( 2^3 \times 3 \times 7 \)
\( 8 \times 3 \times 7 = 24 \times 7 = 168 \)
Final Answer:
168
โโ (2)
Question 22 (2 marks)
Here is a right-angled triangle.
Work out the value of \( x \).
๐ Worked Solution
Step 1: Identify the Theorem
๐ก Pythagoras’ Theorem: \( a^2 + b^2 = c^2 \)
Where \( c \) is the longest side (hypotenuse).
Here, the hypotenuse is 8.5. The other sides are 4 and \( x \).
Step 2: Rearrange to find a shorter side
When finding a shorter side, we subtract the square of the other side from the square of the hypotenuse.
๐ฉ Calculator:
\( 8.5^2 = 72.25 \)
\( 4^2 = 16 \)
\[ x^2 = 72.25 – 16 = 56.25 \]Step 3: Solve for \( x \)
๐ฉ Calculator: โ 56.25 =
Final Answer:
\( x = 7.5 \)
โโ (2)
Question 23 (4 marks)
\( T = 4m^2 – 11 \)
(a) Work out the value of \( T \) when \( m = -3 \)
(b) Make \( p \) the subject of the formula \( d = 3p + 4 \)
๐ Worked Solution
Part (a): Substitution
๐ก Caution: When squaring a negative number, use brackets! \( (-3)^2 \) is positive 9.
Part (b): Rearranging
๐ก Goal: Get \( p \) on its own.
Equation: \( d = 3p + 4 \)
1. Subtract 4 from both sides:
\[ d – 4 = 3p \]2. Divide both sides by 3:
\[ \frac{d – 4}{3} = p \]So,
\[ p = \frac{d – 4}{3} \]Final Answer:
(a) 25
(b) \( p = \frac{d – 4}{3} \)
โโโโ (4)
Question 24 (5 marks)
Rick, Selma and Tony are playing a game with counters.
- Rick has some counters.
- Selma has twice as many counters as Rick.
- Tony has 6 counters less than Selma.
In total they have 54 counters.
the number of counters Rick has : the number of counters Tony has = \( 1 : p \)
Work out the value of \( p \).
๐ Worked Solution
Step 1: Define variables
๐ก Strategy: Use algebra. Let \( x \) be the number of counters Rick has.
Rick = \( x \)
Selma = \( 2x \) (twice as many as Rick)
Tony = \( 2x – 6 \) (6 less than Selma)
Step 2: Form an equation
The total is 54.
Simplify:
\[ 5x – 6 = 54 \]Step 3: Solve for \( x \)
Add 6 to both sides:
\[ 5x = 60 \]Divide by 5:
\[ x = 12 \]Step 4: Find number of counters for each
Rick = \( x = 12 \)
Tony = \( 2(12) – 6 = 24 – 6 = 18 \)
Step 5: Use the ratio
Ratio Rick : Tony = \( 12 : 18 \)
We need it in the form \( 1 : p \).
Divide both sides by 12 (to get 1 on the left):
\[ 1 : \frac{18}{12} \]Simplify \( \frac{18}{12} = 1.5 \)
\[ 1 : 1.5 \]So \( p = 1.5 \)
Final Answer:
\( p = 1.5 \)
โโโโโ (5)
Question 25 (4 marks)
Jo is going to buy 15 rolls of wallpaper.
Here is some information about the cost of rolls of wallpaper from each of two shops.
Chic Decor
3 rolls for ยฃ36
Style Papers
Pack of 5 rolls
normal price ยฃ70
12% off the normal price
Jo wants to buy the 15 rolls of wallpaper as cheaply as possible.
Should Jo buy the wallpaper from Chic Decor or from Style Papers?
You must show how you get your answer.
๐ Worked Solution
Step 1: Calculate cost at Chic Decor
๐ก Info: 3 rolls cost ยฃ36. We need 15 rolls.
How many sets of 3 are in 15?
Cost at Chic Decor: ยฃ180
Step 2: Calculate cost at Style Papers
๐ก Info: Pack of 5 rolls costs ยฃ70. We need 15 rolls.
How many packs of 5?
Normal price = \( 3 \times 70 = 210 \)
Apply discount: 12% off.
12% of 210:
\[ 0.12 \times 210 = 25.20 \]Discounted Price:
\[ 210 – 25.20 = 184.80 \]Cost at Style Papers: ยฃ184.80
(Alternative Multiplier Method: \( 210 \times 0.88 = 184.80 \))
Step 3: Comparison
Chic Decor: ยฃ180.00
Style Papers: ยฃ184.80
ยฃ180 < ยฃ184.80
Final Answer:
Chic Decor is cheaper.
โโโโ (4)
Question 26 (2 marks)
The table gives information about the lengths, in cm, of some pieces of string.
| Length (t cm) | Frequency |
|---|---|
| 0 < t โค 10 | 15 |
| 10 < t โค 20 | 20 |
| 20 < t โค 30 | 50 |
| 30 < t โค 40 | 25 |
| 40 < t โค 50 | 5 |
Amos draws a frequency polygon for the information in the table.
Write down two mistakes that Amos has made.
๐ Worked Solution
Step 1: Analyzing Frequency Polygons
๐ก Rule 1: Points must be plotted at the midpoint of the interval (e.g., for \( 0 < t \leq 10 \), plot at \( x = 5 \)).
๐ก Rule 2: The scale on the axes must be linear (go up in equal steps).
Check points: Amos plotted at 10, 20, 30… (the end of the intervals). This is incorrect.
Check scale: The y-axis goes 0, 10, 20, 30, 50, 60. The number 40 is missing.
Final Answer:
1. The points should be plotted at the midpoints (e.g. 5, 15, 25…), not the end points.
2. The frequency scale (y-axis) is missing 40 (or is not linear).
โโ (2)
Question 27 (4 marks)
Jessica runs for 15 minutes at an average speed of 6 miles per hour.
She then runs for 40 minutes at an average speed of 9 miles per hour.
It takes Amy 45 minutes to run the same total distance that Jessica runs.
Work out Amy’s average speed.
Give your answer in miles per hour.
๐ Worked Solution
Step 1: Jessica’s First Run
๐ก Formula: \( \text{Distance} = \text{Speed} \times \text{Time} \)
โ ๏ธ Units: Speed is in miles per hour, so time must be in hours.
15 minutes = \( \frac{15}{60} \) hours = 0.25 hours.
Step 2: Jessica’s Second Run
Time = 40 minutes = \( \frac{40}{60} \) hours = \( \frac{2}{3} \) hours.
Step 3: Total Distance
Step 4: Amy’s Speed
๐ก Formula: \( \text{Speed} = \frac{\text{Distance}}{\text{Time}} \)
Distance = 7.5 miles.
Time = 45 minutes = \( \frac{45}{60} \) hours = 0.75 hours.
๐ฉ Calculator: 7.5 รท 0.75 =
10 mph
Final Answer:
10 miles per hour
โโโโ (4)
Question 28 (3 marks)
The diagram shows rectangle \( STUV \).
\( TQU \) and \( SRV \) are straight lines.
All measurements are in cm.
The area of trapezium \( QUVR \) is \( A \text{ cm}^2 \)
Show that \( A = 2x^2 + 20x \)
๐ Worked Solution
Step 1: Identify dimensions of Trapezium \( QUVR \)
A trapezium has two parallel sides. Here, the vertical sides \( QU \) (not vertical?) No, \( STUV \) is a rectangle, so \( TU \) is parallel to \( SV \).
The parallel sides are the top and bottom edges.
Height of trapezium: The distance between parallel lines is the height of the rectangle = \( 4x \).
Parallel Side 1 (Base RV): Length = 5.
Parallel Side 2 (Top QU): We need to find this length.
Total bottom length \( SV = SR + RV = 3x + 5 \)
Top length \( TU \) must equal bottom length \( SV \) (rectangle property).
\( TU = 3x + 5 \)
We know \( TQ = 2x \).
\( QU = TU – TQ = (3x + 5) – 2x = x + 5 \)
Step 2: Apply Area Formula
๐ก Formula: \( \text{Area} = \frac{a + b}{2} \times h \)
Where \( a \) and \( b \) are parallel sides, and \( h \) is height.
\( a = 5 \) (side RV)
\( b = x + 5 \) (side QU)
\( h = 4x \) (side UV)
Step 3: Simplify
Divide \( 4x \) by 2 first:
\[ A = (x + 10) \times 2x \]Expand the brackets:
\[ A = 2x(x) + 2x(10) \] \[ A = 2x^2 + 20x \]Final Answer:
Shown correctly: \( A = 2x^2 + 20x \)
โโโ (3)
Question 29 (2 marks)
Change 30 metres per second to kilometres per hour.
๐ Worked Solution
Step 1: Convert seconds to hours
๐ก Strategy: There are 60 seconds in a minute, and 60 minutes in an hour. So there are \( 60 \times 60 = 3600 \) seconds in an hour.
If you travel 30 metres in 1 second, you travel \( 30 \times 3600 \) metres in 1 hour.
Step 2: Convert metres to kilometres
๐ก Strategy: There are 1000 metres in 1 kilometre. Divide by 1000.
Final Answer:
108 kilometres per hour
โโ (2)
Question 30 (2 marks)
The value of Michelle’s car has decreased by 15%.
The car now has a value of ยฃ13,600.
Work out the value of Michelle’s car before the decrease.
๐ Worked Solution
Step 1: Understand Reverse Percentages
๐ก Concept: The original price represents 100%.
If it decreased by 15%, the new price is:
\[ 100\% – 15\% = 85\% \]So, ยฃ13,600 is equal to 85% of the original price.
Step 2: Calculate the original price
๐ก Method: Divide the current price by the percentage multiplier (0.85).
๐ฉ Calculator: 13600 รท 0.85 =
16000
Final Answer:
ยฃ16,000
โโ (2)