Keystones — Capstone
Five GCSE retrieval questions · 11 January 2026 · mathsvault.uk/keystones
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1. Number Error intervals
53 is rounded to the nearest integer. What is the error interval?
Answer: 52.5 ≤ x < 53.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 30 and 3x - y = 12
Answer: x = 6, y = 6 -
3. Geometry Distance between two points
Find the distance between (-7, -1) and (4, 8)
Answer: 14.21 -
4. Ratio Repeated percentage change
A car worth £11,362.00 depreciates by 20% each year for 5 years. What is it worth after 5 years?
Answer: £3,723.10 -
5. Statistics Expected frequency
A bag has 4 red out of 14 balls. If you pick 67 times (with replacement), how many times would you expect red?
Answer: 19.1