Keystones — Capstone
Five GCSE retrieval questions · 8 September 2026 · mathsvault.uk/keystones
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1. Number Error intervals
27 is rounded to the nearest integer. What is the error interval?
Answer: 26.5 ≤ x < 27.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 30 and 3x - y = 1
Answer: x = 3, y = 8 -
3. Geometry Distance between two points
Find the distance between (-4, 0) and (4, 7)
Answer: 10.63 -
4. Ratio Repeated percentage change
A car worth £5,462.00 depreciates by 17% each year for 4 years. What is it worth after 4 years?
Answer: £2,592.17 -
5. Statistics Expected frequency
A bag has 2 red out of 10 balls. If you pick 59 times (with replacement), how many times would you expect red?
Answer: 11.8