Keystones — Capstone
Five GCSE retrieval questions · 2 June 2026 · mathsvault.uk/keystones
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1. Number Error intervals
92 is rounded to the nearest integer. What is the error interval?
Answer: 91.5 ≤ x < 92.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 39 and 3x - y = 20
Answer: x = 9, y = 7 -
3. Geometry Distance between two points
Find the distance between (-8, -7) and (9, 6)
Answer: 21.4 -
4. Ratio Repeated percentage change
A car worth £5,487.00 depreciates by 12% each year for 3 years. What is it worth after 3 years?
Answer: £3,739.24 -
5. Statistics Expected frequency
A bag has 3 red out of 9 balls. If you pick 68 times (with replacement), how many times would you expect red?
Answer: 22.7