Question

Fifteen years from now Ravi's age will be four times his present age. What is Ravi's present age?
Class 8 Maths NCERT Ch 2 ex 2.2 q12

Answer 1

Given:

• Fifteen years from now Ravi's age will be four times his present age.

To find:

• The Present age of Ravi?

Solution: Let's say, that the present age of Ravi be n years.

After Fifteen years, his age —

⇥ Ravi's age + 15 years

⇥ n + 15 years

⠀⠀━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

• F r o m G i v e n C o n d i t i o n :

• Fifteen years from now Ravi's age will be four times his present age.

Therefore$,$

★ 4 × (Ravi's age) = (Present age + 15) ★

➟ ⠀4n = n + 15

➟ ⠀4n – n = 15

➟⠀ 3n = 15

➟ ⠀n = 15⁄3

➟⠀ n = 5

∴ Hence, present age of Ravi is 5 years.

⠀⠀━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Answer 2

Given :-

Fifteen years from now Ravi's age will be four times his present age.

To Find :-

Ravi's present age

Solution :-

Let us assume that the present age of Ravi be r

Present age of Ravi = r

Age of Ravi after 15 years = r + 15

4r = r + 15

4r - r = 15

3r = 15

r = 15/3

r = 5 years

Present age of Ravi is 5 years

V E R I F I C A T I O N :

4r = r + 15

4(5) = 5 + 15

20 = 20

Also,

After 15 years

Age of Ravi = 5 + 15 = 20 years

Which is 4 time his present age