Keystones — Capstone
Five GCSE retrieval questions · 18 April 2026 · mathsvault.uk/keystones
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1. Number Error intervals
93 is rounded to the nearest integer. What is the error interval?
Answer: 92.5 ≤ x < 93.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 36 and 3x - y = 10
Answer: x = 6, y = 8 -
3. Geometry Distance between two points
Find the distance between (-1, 1) and (9, 4)
Answer: 10.44 -
4. Ratio Repeated percentage change
A car worth £12,691.00 depreciates by 19% each year for 5 years. What is it worth after 5 years?
Answer: £4,425.08 -
5. Statistics Expected frequency
A bag has 4 red out of 11 balls. If you pick 83 times (with replacement), how many times would you expect red?
Answer: 30.2