Question

At present the difference between ages of two persons are 10 years.15 years ago, the elder was twice as old as the younger.Find their present ages.

Answer 1

Let the present age of younger cousin be x.

15 years ago it will be (x-15) years.

Let the present age of elder cousin be x + 10.              -------------(1)
 
15 years ago it will be x + 10 - 15 = x + 5.

Given, The elder was twice as old as younger i.e

x - 5 = 2(x-15)

x-5 = 2x - 30

x = 25.

Substitute x in (1), we get 
 
x = 35.

Their present ages are 25 and 35.


Hope this helps!                

Answer 2

Answer:

Let the age of elder be x

Let the age of younger be y

x = 10 + y            ............. i)

(x - 15) = 2 (y - 15) ..............ii)

On substituting 1st equation with the second

10 + y - 15 = 2y - 30

y - 2y = -30 + 15 - 10

-y = -25

y = 25.

elder one = 25 + 10

                = 35.

younger one = 25