Question

The age of the two friends were in the ration of 6:5. If the sum of their ages is 55. Then after how many years their ratio will become 8:7?
a.11
b.7
c.10
d.12

Answer 1

Ratio is 6:5, the sum is 55.

6x + 5x = 55

11x = 55

x = 55/11

x = 5

Their ages now are:

6*5 = 30 years old

5*5 = 25 years old

Lets find their ages for the ratio of 8:7

Let y = years:

30 +y / 25 +y = 8/7

Cross multiply:

8(25 +y) = 7(30 +y)

200 + 8y = 210 + 7y

y = 10

The answer is C.10