Question

The ages of A &B are in the ratio 5;7.Eight years ago,their ages were in the ratio7:13.Find their present age.

Answer 1

let the present age of A&B be 5x and 7x years.
A age 8 years ago=(5x-8) years.
B age 8 years ago=(7x-8) years.

5x-8
____=7:13
7x-8

13 (5x-8)=7 (7x-8)

65x-104=49x-56

65x-49x=-56+104

16x=48

x=48÷16=3

A age=5×3=15 years

B age=7×3=21 years

Hope its helps...

Answer 2

Ratio of their present ages are 5:7
Let their present age be 5x and 7x
8years ago their ages would be 5x-8 , 7x-8
These ages were said to be in the ratio 7:13
Therefore,
5x-8 : 7x-8 = 7:13
= 5x-8 / 7x-8 = 7 / 13
= (5x-8) * 13 = 7 * (7x-8)
= 65x - 104 = 49x - 56
= 65x - 49x = -56 + 104
= 16x = 48
= x = 48/16
= x = 3
Now we got the value of x
So present ages of A and B are
A = 5x =5*3 = 15 years
B = 7x = 21 years

Here's the solution.....