Keystones — Lintel
Five GCSE retrieval questions · 29 April 2026 · mathsvault.uk/keystones
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1. Number Product of primes
Write 72 as a product of its prime factors
Answer: 2³ × 3² -
2. Algebra Linear simultaneous equations
Solve: 4x + 3y = 38 and 3x + 3y = 30
Answer: x = 8, y = 2 -
3. Geometry Pythagoras — short side
Calculate the missing side: a = 24cm, c = 29cm
Answer: 16.3cm -
4. Ratio Combining two ratios
a:b is 3:2 and b:c is 1:2. Find a:b:c.
Answer: 9:6:12 -
5. Statistics Expected frequency
A bag has 3 red out of 12 balls. If you pick 54 times (with replacement), how many times would you expect red?
Answer: 13.5