Keystones — Capstone
Five GCSE retrieval questions · 26 February 2026 · mathsvault.uk/keystones
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1. Number Error intervals
47 is rounded to the nearest integer. What is the error interval?
Answer: 46.5 ≤ x < 47.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 36 and 3x - y = 21
Answer: x = 9, y = 6 -
3. Geometry Distance between two points
Find the distance between (-3, 2) and (7, 12)
Answer: 14.14 -
4. Ratio Repeated percentage change
A car worth £11,371.00 depreciates by 16% each year for 3 years. What is it worth after 3 years?
Answer: £6,739.64 -
5. Statistics Expected frequency
A bag has 5 red out of 13 balls. If you pick 91 times (with replacement), how many times would you expect red?
Answer: 35