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Proportion (harder)

Free Printable Proportion (harder) PDF Worksheets, Revision Guide & GCSE Past Paper Questions (Grade 7)

Download free proportion (harder) worksheets (PDF), GCSE maths past paper questions and worked solutions for Proportion (harder) (7C). This is a Grade 7 ratio & proportion topic from the GCSE questions by topic collection for Higher tier GCSE Maths (Edexcel, AQA, OCR and IGCSE).

The free PDF worksheets table below brings together printable question booklets (Qs) and worked answers or mark schemes (Ans) from Maths Genie, Corbett Maths, Dr Frost, 1st Class Maths, Maths4EveryOne, Metatutor, Maths Takeaway, Dr Austin, Maths DIY, GCSE Maths Rocket, E Classroom and PMT, along with past paper question booklets.

Below the worksheet links you can read our proportion (harder) revision notes and worked examples with diagrams, try real GCSE past paper proportion (harder) questions with step-by-step solutions, or download a PDF of all proportion (harder) worksheet links.

Free Proportion (harder) PDF Worksheets & Answers

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GCSE Maths Grade 7 Revision Notes & Method

Guide to Proportion (harder): Explanation, Diagrams & Worked Examples

Download Printable One Page Guide (PDF)

Explanation:

Translate the proportion statement into an algebraic equation using a constant of proportionality k: if y is directly proportional to xn, write y = kxn; if y is inversely proportional to xn, write y = kxn. Substitute the given pair of values to find k and write the full formula before finding any unknown values.

For compound three-variable problems (where y depends on x and x depends on z), substitute the second formula directly into the first and simplify the powers and constants carefully. Remember to take both roots or the positive physical root when solving for x2 or √x.

Example 1: y is inversely proportional to x2. Given y = 5 when x = 6, find x when y = 20 (x > 0).

Solution:

y = kx2 ⇒ 5 = k62
k = 5 × 36 = 180, so y = 180x2
When y = 20: 20 = 180x2 ⇒ x2 = 18020 = 9
Since x > 0, x = √9 = 3
Answer: x = 3

Example 2: P = 3Q2 and Q is inversely proportional to √R. Given Q = 4 when R = 9, write P in terms of R.

Solution:

Q = k√R ⇒ 4 = k√9 ⇒ k = 4 × 3 = 12
Substitute Q = 12√R into P = 3Q2:
P = 3 × (12√R)2 = 3 × 144R
Answer: P = 432R
Scanned GCSE Exam Questions & Worked Solutions

GCSE Past Paper Proportion (harder) Questions & Answers

Past Paper Example 1 GCSE Nov 2021 3H Q8 2 marks
Work out
(a) Sketch graph for y is directly proportional to x (1) (b) Sketch graph for y is inversely proportional to x (1)
(a) Using the axes below, sketch a graph to represent the statement
y is directly proportional to x
[1 mark]
xyO
(b) Using the axes below, sketch a graph to represent the statement
y is inversely proportional to x
[1 mark]
xyO
Worked Solution & Mark Scheme (2 marks)
Part (a) Solution:
y = kx is a straight line through (0, 0) B1
xyO
Answer (a): Straight line with positive gradient passing through the origin O
Part (b) Solution:
y = k/x is a decreasing hyperbola in quadrant 1 B1
xyO
Answer (b): Reciprocal curve y = k/x in the first quadrant asymptotic to both axes
Past Paper Example 2 OCR Jun 2023 1F Q22 4 marks
Hiro and Taylor are both electricians.
Hiro **does not** charge to visit a house but charges a fixed rate per hour for the work needed.
This graph shows the relationship between the hours worked and the total charge made by Hiro.
OTotalchargeHours worked
(a) Explain how this graph shows that Hiro’s total charge is directly proportional to the hours worked. [2 marks]
(b) Taylor **does** charge to visit a house and charges the same fixed rate per hour as Hiro for the work needed.
On the axes above, draw a graph to show the relationship between the hours worked and the total charge made by Taylor.
[2 marks]
Worked Solution & Mark Scheme (4 marks)
Part (a) Solution:
A graph showing direct proportion must be a straight line through the origin. M1 C1
Answer (a): It is a straight line that passes through the origin (0, 0).
Part (b) Solution:
Same hourly rate ⇒ same gradient (parallel line) M1
call-out charge ⇒ positive y-intercept. A1
Answer (b): Straight line parallel to Hiro’s line with a positive vertical intercept.
Past Paper Example 3 OCR Nov 2023 4H Q8 2 marks
Here are sketches of six graphs, labelled **A** to **F**.
AyxOByxOCyxODyxOEyxOFyxO
(a) y is directly proportional to x. [1 mark]
(b) y is inversely proportional to x. [1 mark]
Worked Solution & Mark Scheme (2 marks)
Part (a) Solution:
Direct proportion y = kx is a straight line through the origin ⇒ Graph C. B1
Answer (a): C
Part (b) Solution:
Inverse proportion y = k/x is a reciprocal curve in the first quadrant ⇒ Graph E. B1
Answer (b): E

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