Keystones — Capstone
Five GCSE retrieval questions · 25 July 2026 · mathsvault.uk/keystones
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1. Number Error intervals
80 is rounded to the nearest integer. What is the error interval?
Answer: 79.5 ≤ x < 80.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 22 and 3x - y = 11
Answer: x = 5, y = 4 -
3. Geometry Distance between two points
Find the distance between (0, 2) and (11, 10)
Answer: 13.6 -
4. Ratio Repeated percentage change
A car worth £7,944.00 depreciates by 18% each year for 5 years. What is it worth after 5 years?
Answer: £2,945.16 -
5. Statistics Expected frequency
A bag has 5 red out of 8 balls. If you pick 135 times (with replacement), how many times would you expect red?
Answer: 84.4