Keystones — Capstone
Five GCSE retrieval questions · 23 July 2026 · mathsvault.uk/keystones
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1. Number Error intervals
75 is rounded to the nearest integer. What is the error interval?
Answer: 74.5 ≤ x < 75.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 20 and 3x - y = 8
Answer: x = 4, y = 4 -
3. Geometry Distance between two points
Find the distance between (1, -8) and (9, 12)
Answer: 21.54 -
4. Ratio Repeated percentage change
A car worth £19,187.00 depreciates by 12% each year for 4 years. What is it worth after 4 years?
Answer: £11,506.35 -
5. Statistics Expected frequency
A bag has 2 red out of 13 balls. If you pick 143 times (with replacement), how many times would you expect red?
Answer: 22