Keystones — Capstone
Five GCSE retrieval questions · 5 January 2026 · mathsvault.uk/keystones
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1. Number Error intervals
63 is rounded to the nearest integer. What is the error interval?
Answer: 62.5 ≤ x < 63.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 30 and 3x - y = 23
Answer: x = 9, y = 4 -
3. Geometry Distance between two points
Find the distance between (-6, -2) and (5, 3)
Answer: 12.08 -
4. Ratio Repeated percentage change
A car worth £14,736.00 depreciates by 19% each year for 4 years. What is it worth after 4 years?
Answer: £6,343.36 -
5. Statistics Expected frequency
A bag has 5 red out of 11 balls. If you pick 108 times (with replacement), how many times would you expect red?
Answer: 49.1