Multiple choice

The present age of a father is equal to sum of the ages of his 4 children. After ten years the sum of the ages of the children will be 1.6 times the age of their father. What is the present age of father?

  1. 36 years

  2. 40 years

  3. 42 years

  4. 45 years
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let F be father's age, S be sum of children's ages. F = S. After 10 years, father is F+10, sum of children is S+40 (each of 4 children ages by 10). (S+40) = 1.6(F+10). Since F=S, F+40 = 1.6F + 16. 24 = 0.6F. F = 40.

AI explanation

Let the father's present age be F and the sum of the 4 children's present ages be C. Since the father's age equals the sum of the children's ages, F equals C. Ten years later, the sum of the children's ages will be C plus 40 because each of the 4 children ages by 10 years, and the father's age will be F plus 10. Using the given relation, C plus 40 equals 1.6 times (F plus 10), and substituting C with F gives F plus 40 equals 1.6F plus 16, which simplifies to 0.6F equals 24. Solving for F gives the father's present age as 40 years.

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