Keystones — Capstone
Five GCSE retrieval questions · 10 September 2026 · mathsvault.uk/keystones
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1. Number Error intervals
22 is rounded to the nearest integer. What is the error interval?
Answer: 21.5 ≤ x < 22.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 38 and 3x - y = 24
Answer: x = 10, y = 6 -
3. Geometry Distance between two points
Find the distance between (2, -7) and (5, 7)
Answer: 14.32 -
4. Ratio Repeated percentage change
A car worth £8,958.00 depreciates by 17% each year for 3 years. What is it worth after 3 years?
Answer: £5,122.07 -
5. Statistics Expected frequency
A bag has 2 red out of 10 balls. If you pick 135 times (with replacement), how many times would you expect red?
Answer: 27