Q4 of 38 Page 88

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 age of the younger brother.

Let the age of younger brother be x years

Therefore, the age of elder brother is (x + 4) years


Now, Five years before, age of younger brother = x-5


Also, age of elder brother = (x + 4) -5


It is given that, 5 years ago(before), their age was in the


ratio 5:7



On cross multiplying, we get,


⇒ 7x – 35 = 5x – 5


⇒ 2x = 30


⇒ x = 15


Therefore, the age of younger brother is 15 years.


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