a boy is older than his sister by 3 years five years ago, the ratio of their ages was 4 : 3 find his present.

B:S = 4x:3x

4x - 3x = 3

x = 3

They were 12 & 9.

Add 5 to that.

So he's now 17 and she's 14

five years ago - - boy - x+3 years

sister - - - x

ratio- - 4:3 so difference is 3 years

4-3- - 1 1--3

five years ago - - - sister : 3*3--9 brother : 4*3--12

present : sister 14 years and brother 17 years old