Keystones — Capstone
Five GCSE retrieval questions · 27 February 2026 · mathsvault.uk/keystones
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1. Number Error intervals
70 is rounded to the nearest integer. What is the error interval?
Answer: 69.5 ≤ x < 70.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 29 and 3x - y = 27
Answer: x = 10, y = 3 -
3. Geometry Distance between two points
Find the distance between (2, -5) and (8, 6)
Answer: 12.53 -
4. Ratio Repeated percentage change
A car worth £18,948.00 depreciates by 22% each year for 5 years. What is it worth after 5 years?
Answer: £5,470.62 -
5. Statistics Expected frequency
A bag has 4 red out of 15 balls. If you pick 121 times (with replacement), how many times would you expect red?
Answer: 32.3