Keystones — Capstone
Five GCSE retrieval questions · 1 November 2026 · mathsvault.uk/keystones
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1. Number Error intervals
51 is rounded to the nearest integer. What is the error interval?
Answer: 50.5 ≤ x < 51.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 38 and 3x - y = 13
Answer: x = 7, y = 8 -
3. Geometry Distance between two points
Find the distance between (0, 1) and (7, 5)
Answer: 8.06 -
4. Ratio Repeated percentage change
A car worth £13,329.00 depreciates by 15% each year for 5 years. What is it worth after 5 years?
Answer: £5,914.15 -
5. Statistics Expected frequency
A bag has 2 red out of 9 balls. If you pick 85 times (with replacement), how many times would you expect red?
Answer: 18.9