Question

John is twenty years youger than his sister Amy.In five years time, Johns age will be half of Amys age.What is Johns age now?

Answer 1

Hi!

Here is the answer to your question.

Let the present age of John be x years.

Since John is 20 years younger than his sister Amy, the present age of Amy is (x + 20) years.

5 years hence, John’s age will be (x + 5) years and Amy’s age will be (x + 20 + 5) years = (x + 25) years.

According to the given condition,

(x + 5) = ½(x + 25)

⇒ 2(x + 5) = (x + 25) [Multiplying both sides by 2]

⇒ 2x + 10 = x + 25

⇒ 2x – x = 25 – 10

⇒ x = 15

∴ John’s present age is 15 years.

Cheers!