Keystones — Capstone
Five GCSE retrieval questions · 23 February 2026 · mathsvault.uk/keystones
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1. Number Error intervals
79 is rounded to the nearest integer. What is the error interval?
Answer: 78.5 ≤ x < 79.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 26 and 3x - y = 17
Answer: x = 7, y = 4 -
3. Geometry Distance between two points
Find the distance between (-8, 2) and (6, 10)
Answer: 16.12 -
4. Ratio Repeated percentage change
A car worth £7,661.00 depreciates by 23% each year for 5 years. What is it worth after 5 years?
Answer: £2,073.67 -
5. Statistics Expected frequency
A bag has 5 red out of 11 balls. If you pick 74 times (with replacement), how many times would you expect red?
Answer: 33.6