Question

the difference between the ages of two brothers today is 4 years. five years ago, the ratio of their ages was 5:7. find the ages of the youngest brother

Answer 1

Let the present age of big bro be x
and present age of small bro be y
x-y=4

5(x-5)=7(y-5)

5x-25=7y-35
5x-7y=-35+25
         =-10

 5x-5y=20
-5x-7y=-10

2y=30
y=15
x-y=4
x=4+15
x=19
so age of small bro is 15 and age of big bro is 19

hope it help..