Question

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.
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Answer 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