Keystones — Capstone
Five GCSE retrieval questions · 15 April 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 = 27 and 3x - y = 24
Answer: x = 9, y = 3 -
3. Geometry Distance between two points
Find the distance between (-8, 0) and (7, 7)
Answer: 16.55 -
4. Ratio Repeated percentage change
A car worth £13,893.00 depreciates by 15% each year for 4 years. What is it worth after 4 years?
Answer: £7,252.23 -
5. Statistics Expected frequency
A bag has 4 red out of 11 balls. If you pick 118 times (with replacement), how many times would you expect red?
Answer: 42.9