Multiple choice

A person's present age is $\displaystyle \frac{2}{5}$th of the age of his mother. After $8$ years, he will be one-half of the age of his mother. How old is the mother at present?

  1. $32$ years
  2. $36$ years
  3. $40$ years
  4. $48$ years
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let mother's age be M. Person's age = 2/5 M. After 8 years: (2/5 M + 8) = 1/2 (M + 8). 4/5 M + 16 = M + 8 => 8 = 1/5 M => M = 40.

AI explanation

Let the present ages of the person and his mother be 2x and 5x. After 8 years, the person's age will be one-half of his mother's age, giving the equation (2x + 8) / (5x + 8) = 1 / 2. Cross-multiplying results in 4x + 16 = 5x + 8, so x = 8. The mother's present age is 5 multiplied by 8, which equals 40 years.

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