This study notes covers Worked Example 3: Recipe Scaling within Proportion for GCSE Mathematics. Revise Proportion in Number for GCSE Mathematics with 12 exam-style questions and 22 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 9 of 15 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 9 of 15
Practice
12 questions
Recall
22 flashcards
Worked Example 3: Recipe Scaling
A recipe uses 300g flour for 4 people. How much flour is needed for 10 people?
Solution
Flour ∝ Number of people (direct proportion)
F = kP where F = flour, P = people
When P = 4, F = 300: 300 = k × 4
k = 300 ÷ 4 = 75
So F = 75P
For 10 people: F = 75 × 10 = 750g
Answer: 750g flour