Keystones — Capstone
Five GCSE retrieval questions · 5 June 2026 · mathsvault.uk/keystones
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1. Number Error intervals
69 is rounded to the nearest integer. What is the error interval?
Answer: 68.5 ≤ x < 69.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 32 and 3x - y = 4
Answer: x = 4, y = 8 -
3. Geometry Distance between two points
Find the distance between (-7, -7) and (5, 5)
Answer: 16.97 -
4. Ratio Repeated percentage change
A car worth £18,330.00 depreciates by 16% each year for 4 years. What is it worth after 4 years?
Answer: £9,125.98 -
5. Statistics Expected frequency
A bag has 3 red out of 13 balls. If you pick 128 times (with replacement), how many times would you expect red?
Answer: 29.5