Multiple choice

The present ages of A and B are in the ratio 3 : 1, respectively. Ten years later, the ratio will be 5 : 2. The present age of A is

  1. 30 years

  2. 90 years

  3. 40 years

  4. 100 years
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let ages be 3x and x. (3x+10)/(x+10) = 5/2. 6x + 20 = 5x + 50, so x = 30. A's age = 3x = 90.

AI explanation

Let the present ages of A and B be 3x and x years, respectively. Ten years later, their ages will be 3x plus 10 and x plus 10, giving the equation 3x plus 10 divided by x plus 10 equals 5 over 2. Cross multiplying yields 6x plus 20 equals 5x plus 50, so x equals 30. The present age of A is 3 times 30, which is 90 years.

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