Keystones — Lintel
Five GCSE retrieval questions · 15 March 2026 · mathsvault.uk/keystones
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1. Number Product of primes
Write 48 as a product of its prime factors
Answer: 2⁴ × 3 -
2. Algebra Linear simultaneous equations
Solve: 5x + 5y = 50 and x + y = 10
Answer: x = 2, y = 8 -
3. Geometry Pythagoras — short side
Find b if a = 15cm and c = 27cm
Answer: 22.45cm -
4. Ratio Combining two ratios
a:b is 3:5 and b:c is 5:7. Find a:b:c.
Answer: 3:5:7 -
5. Statistics Expected frequency
A bag has 3 red out of 12 balls. If you pick 130 times (with replacement), how many times would you expect red?
Answer: 32.5