Find the Ratio Between Younger Brother and Elder Brother
Answer: (4) 3:7
Let the age of elder brother be x years and smaller brother be y years.
Then, According to first condition,
x – y = 8 —– (i)
and sum is x+y
Again, it is given that the sum of their ages will double after 10 years. The equations thus formed is
2(x+y) = (x+10) + (y+10)
Thus, 2x + 2y = x+y+20
x+y=20 —— (ii)
adding (i) and (ii), we get
2x = 28
x = 14 years
and y is 14- 8 = 6 years
Therefore, ratio of younger to elder brother is 6/14 = 3/7
Then, the ration of the age of the younger brother to that of the elder brother = 3 : 7.
Hence, the answer is (4) 3 : 7.