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Ai Tong 2025 P6 Maths Prelim — Paper 1 Booklet A Q15 Solution

Paper 1 Booklet A · Q15 · 2 marks · Ratio

Question

4 years ago, the ratio of Calvin's age to Lina's age was 2 : 7. In 8 years' time, Calvin's age will be $\frac{2}{5}$ of Lina's age. How old is Calvin now?
Answer: 3

Worked solution

  1. \text{4 years ago: Calvin} = 2u,\ \text{Lina} = 7u
  2. \text{In 8 years: Calvin} = 2u + 12,\ \text{Lina} = 7u + 12
  3. 2u + 12 = \frac{2}{5}(7u + 12)
  4. 5(2u + 12) = 2(7u + 12)
  5. 10u + 60 = 14u + 24
  6. 4u = 36
  7. u = 9
  8. \text{Calvin now} = 2(9) + 4 = 22 \text{ years old}

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