Question

the differences between the ages of two cousins is 10 years 15 years ago if the elder one was twice as old as the younger one find their present ages

Answer 1

Let the present age be x then 2nd's age= x+10

15 years ago'
(x-15)*2=(x+10-15)
2x-30=x-5
2x-x=30-5
x=25 years
x+10=35 years

Answer 2

The "present age" of younger 25.

The "present age" of elder is 35.

Given:

Age difference between two cousins is 10 years.

Elder one is twice older than younger one, 15 years ago.

To find:

To identify the present age of younger and elder cousin.

Solution:

Let y be the "age of the younger cousin".

The age of the elder cousin = y + 10

From the condition which is 15 years ago,

The age of younger cousin, 15 years ago = y - 15

The age of elder cousin, 15 years ago = y + 10 - 15 = y - 5

Again from the condition, we get

$y-5=2(y-15)$

$y-5=2y-30$

$2y-y=30-5$

$y=25$

Thus,

$Age \ of \ elder \ cousin = y + 10 = 25 + 10 = 35$