Keystones — Capstone
Five GCSE retrieval questions · 13 September 2026
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1. Number Error intervals
81 is rounded to the nearest integer. What is the error interval?
Answer: 80.5 ≤ x < 81.5 -
2. Algebra Linear simultaneous equations
Solve: 2x + 3y = 18 and 3x - y = 16
Answer: x = 6, y = 2 -
3. Geometry Distance between two points
Find the distance between (-8, 2) and (8, 6)
Answer: 16.49 -
4. Ratio Repeated percentage change
A car worth £18,952.00 depreciates by 18% each year for 5 years. What is it worth after 5 years?
Answer: £7,026.26 -
5. Statistics Expected frequency
A bag has 4 red out of 13 balls. If you pick 77 times (with replacement), how many times would you expect red?
Answer: 23.7