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WAEC Mathematics 2021 Question 9

Question 9

Linear and Simultaneous Equations

Mensah is 5 years old and Joyce is thrice as old as Mensah. In how many years will Joyce be twice as old as Mensah?

  1. A.3 years
  2. B.10 years
  3. C.5 years
  4. D.15 years
Show the answer and explanation

Answer: C (5 years)

Explanation

Joyce is 15. In n years: 15 + n = 2(5 + n), so 15 + n = 10 + 2n and n = 5.