Direct & inverse proportion
Edexcel GCSE Maths revision on Direct & inverse proportion. Aligned to the Pearson Edexcel GCSE Mathematics 1MA1 specification. This bank has 16 practice questions on this topic.
Sample questions (3 of 16)
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Question 1
If y is directly proportional to x, and y = 12 when x = 4, find y when x = 7.
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Answer: 21
Direct proportion: y = kx. Find k: 12 = k x 4 -> k = 3. New y: y = 3 x 7 = 21.
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Question 2
If y is inversely proportional to x, and y = 8 when x = 3, find y when x = 6.
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Answer: 4
Inverse proportion: y = k/x. Find k: 8 = k/3 -> k = 24. New y: 24/6 = 4. Note: double x -> y halves.
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Question 3
4 workers build a wall in 6 days. How long for 3 workers?
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Answer: 8
Inverse proportion: fewer workers = longer time. Total = 4x6 = 24 worker-days. With 3 workers: 24/3 = 8 days.
Want to test yourself on the remaining cards for this topic?
13 more questions on Direct & inverse proportion — plus mistakes tracking and spaced repetition across the whole Maths spec.