Answer 1

Man’s age = 42 years

Son’s age = 12 years

Let after x years the age of the son will be half the age of the man.

Man’s age after x years = (42 + x) years

Son’s age after x years = (12 + x) years

According to the statement :

`12 + "x" = (42 + "x")/2`

⇒ 2(12 + x) = 42 + x   ...(by cross multiplying)

⇒ 24 + 2x = 42 + x

⇒ 2x - x = 42 - 24

⇒ x = 18

Hence after 18 years, the age of the son will be half the age of the man