Keystones — Capstone
Five GCSE retrieval questions · 9 January 2026 · mathsvault.uk/keystones
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1. Number Error intervals
93 is rounded to the nearest integer. What is the error interval?
Answer: 92.5 ≤ x < 93.5 -
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 (-1, -2) and (11, 5)
Answer: 13.89 -
4. Ratio Repeated percentage change
A car worth £5,208.00 depreciates by 14% each year for 5 years. What is it worth after 5 years?
Answer: £2,449.98 -
5. Statistics Expected frequency
A bag has 3 red out of 10 balls. If you pick 65 times (with replacement), how many times would you expect red?
Answer: 19.5