Multiple choice

Ten years ago, a man was seven times as old as his son. Two years hence, twice his age will be equal to five times the age of his son. What is the present age of his son?

  1. 15 years

  2. 13 years

  3. 12 years

  4. 14 years

  5. None
Reveal answer Fill a bubble to check yourself
D Correct answer
AI explanation

Let the present ages of the man and his son be M and S. Ten years ago, their ages were M - 10 and S - 10, giving the equation M - 10 = 7(S - 10), which simplifies to M = 7S - 60. Two years hence, the equation is 2(M + 2) = 5(S + 2); substituting M gives 2(7S - 58) = 5S + 10. Solving 14S - 116 = 5S + 10 yields 9S = 126, so the son's present age is 14 years.

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