Ratio & ProportionStudy Notes

Worked Example 2: Unitary Method

Part of Direct Proportion — GCSE Mathematics

This study notes covers Worked Example 2: Unitary Method within Direct Proportion for GCSE Mathematics. Revise Direct Proportion in Ratio & Proportion for GCSE Mathematics with 15 exam-style questions and 12 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 6 of 8 in this topic. Use this study notes to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 6 of 8

Practice

15 questions

Recall

12 flashcards

Worked Example 2: Unitary Method

6 bottles of water cost £4.50. How much do 10 bottles cost?

Step 1 Find cost of 1 bottle

1 bottle = £4.50 ÷ 6 = £0.75

Step 2 Find cost of 10 bottles

10 bottles = £0.75 × 10 = £7.50

Keep building this topic

Read this section alongside the surrounding pages in Direct Proportion. That gives you the full topic sequence instead of a single isolated revision point.

Worked Example 1: Using the Formula Worked Example 3: Best Buy Problem What is Direct Proportion?Key Features of Direct Proportion

Practice Questions for Direct Proportion

Which of the following correctly reads the mathematical statement y ∝ x?

A. y is inversely proportional to x
B. y is directly proportional to x
C. y equals x
D. y is greater than x

1 markfoundation

Explain what it means for y to be directly proportional to x. Your answer should refer to the equation and the graph.

2 marksstandard

Quick Recall Flashcards

What does the graph of y = kx look like?

A straight line passing through the origin (0, 0). The gradient of the line equals k. If the line does NOT pass through (0,0), it is NOT direct proportion.

What does the symbol ∝ mean?

'is proportional to' y ∝ x means 'y is proportional to x' This is equivalent to writing y = kx for some constant k.

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Worked Example 1: Using the Formula

Worked Example 3: Best Buy Problem