the age of A is one-third of the age of B. After 15 years, the age of A will be half of the age ofB. Find their present ages.

July 25, 2021

By Melanie

1 thought on “the age of A is one-third of the age of B. After 15 years, the age of A will be half of the age ofB. Find their present ages.<br /”

1. Given:

   • The age of A is one-third of the age of B. After 15 years, the age of A will be half of the age of B.

   To Find:

   • Their present ages.

   Solution:

   • Let the present age of B be x years.

   • Then, the present age of A is x/3 years.

   • After 15 years, age of A will be ( x/3 + 15) years.

   According to the question,

   After 15 years, The age of A will be half of the age of B.

   ∴ 1/3x + 15 = 1/2 (x + 15)

   ➟ x/3 + 15 = x/2 + 15/2

   ➟ x/3 – x/2 = 15/2 – 5

   ➟ 2x – 3x/6 = 15 – 30/2

   ➟ –x/6 = –15/2

   ➟ –2x = –90

   ➟ x = 45

   • Hence, Age of A = 45/3 = 15 years

   • Age of B = 45 years

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