Keystones — Capstone
Five GCSE retrieval questions · 25 February 2026 · mathsvault.uk/keystones
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1. Number Error intervals
87 is rounded to the nearest integer. What is the error interval?
Answer: 86.5 ≤ x < 87.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 32 and 3x - y = 26
Answer: x = 10, y = 4 -
3. Geometry Distance between two points
Find the distance between (-6, -4) and (11, 12)
Answer: 23.35 -
4. Ratio Repeated percentage change
A car worth £5,520.00 depreciates by 16% each year for 3 years. What is it worth after 3 years?
Answer: £3,271.73 -
5. Statistics Expected frequency
A bag has 3 red out of 10 balls. If you pick 123 times (with replacement), how many times would you expect red?
Answer: 36.9