After 8 years, a man will be 3 times as much old as he is now. After how much…

Given:

Age after 8 years = 3 × Present age

Concept used:

Using concept of linear equation.

Calculation:

Let the present age of man be x years

Let n years after the age will be 5 times of present age.

According to the question,

Age after 8 years = 3 × Present age

⇒ x + 8 = 3x

⇒ 2x = 8

⇒ x = 4

After n years = 5 × Present age

⇒ x + n = 5x

⇒ 4 + n = 20

⇒ n = 16 years

∴ After 16 years the age will be 5 times of present age.