Multiple choice

Father's age is three times the sum of ages of his two children. After five years his age will be twice the sum of ages of two children. The age of the father is

  1. $41$
  2. $45$
  3. $40$

  4. None
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let F be father's age and S be sum of children's ages. F = 3S. After 5 years, F+5 = 2(S+10) (since each child ages 5 years). F+5 = 2S+20. Substituting F=3S: 3S+5 = 2S+20, so S=15. Father's age F = 3*15 = 45.

AI explanation

Let the sum of the children's present ages be S, making the father's present age 3S. In five years, the sum of the children's ages will be S + 10, and the father's age will be 3S + 5. The problem states that 3S + 5 equals 2 times S + 10, so solving 3S + 5 = 2S + 20 gives S = 15. The father's present age is 3 times 15, which is 45.

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