Keystones — Lintel
Five GCSE retrieval questions · 23 September 2026 · mathsvault.uk/keystones
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1. Number Product of primes
Express 120 as a product of prime factors
Answer: 2³ × 3 × 5 -
2. Algebra Linear simultaneous equations
Solve: 5x + 4y = 30 and 2x + 3y = 19
Answer: x = 2, y = 5 -
3. Geometry Pythagoras — short side
Find b if a = 6cm and c = 15cm
Answer: 13.75cm -
4. Ratio Combining two ratios
a:b is 1:2 and b:c is 4:5. Find a:b:c.
Answer: 2:4:5 -
5. Statistics Expected frequency
A bag has 3 red out of 13 balls. If you pick 89 times (with replacement), how many times would you expect red?
Answer: 20.5