Keystones — Capstone
Five GCSE retrieval questions · 8 January 2026 · mathsvault.uk/keystones
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1. Number Error intervals
48 is rounded to the nearest integer. What is the error interval?
Answer: 47.5 ≤ x < 48.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 29 and 3x - y = 5
Answer: x = 4, y = 7 -
3. Geometry Distance between two points
Find the distance between (-2, -1) and (7, 6)
Answer: 11.4 -
4. Ratio Repeated percentage change
A car worth £15,449.00 depreciates by 16% each year for 5 years. What is it worth after 5 years?
Answer: £6,460.96 -
5. Statistics Expected frequency
A bag has 2 red out of 9 balls. If you pick 75 times (with replacement), how many times would you expect red?
Answer: 16.7