Keystones — Capstone
Five GCSE retrieval questions · 21 July 2026 · mathsvault.uk/keystones
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1. Number Error intervals
66 is rounded to the nearest integer. What is the error interval?
Answer: 65.5 ≤ x < 66.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 40 and 3x - y = 16
Answer: x = 8, y = 8 -
3. Geometry Distance between two points
Find the distance between (0, -4) and (3, 3)
Answer: 7.62 -
4. Ratio Repeated percentage change
A car worth £6,605.00 depreciates by 18% each year for 4 years. What is it worth after 4 years?
Answer: £2,986.26 -
5. Statistics Expected frequency
A bag has 2 red out of 11 balls. If you pick 138 times (with replacement), how many times would you expect red?
Answer: 25.1