Keystones — Capstone
Five GCSE retrieval questions · 11 September 2026 · mathsvault.uk/keystones
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1. Number Error intervals
85 is rounded to the nearest integer. What is the error interval?
Answer: 84.5 ≤ x < 85.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 17 and 3x - y = 9
Answer: x = 4, y = 3 -
3. Geometry Distance between two points
Find the distance between (-1, 2) and (4, 3)
Answer: 5.1 -
4. Ratio Repeated percentage change
A car worth £14,244.00 depreciates by 22% each year for 3 years. What is it worth after 3 years?
Answer: £6,759.52 -
5. Statistics Expected frequency
A bag has 5 red out of 14 balls. If you pick 93 times (with replacement), how many times would you expect red?
Answer: 33.2