The ratio between the ages of x and y at present is 3:4. Five years hence, the ratio of their ages will be 4:5; what is the present age of y in years ?

Explanation

Let the present ages of x and y be 3a,4a respectively After 5 years, their ages will be 3a+5 and 4a+5 3a+5 4 4a+5 = 5 ==> 5(3a+5) = 4(4a+5) ==> 15a+25 = 16a+20 ==> a=5 Present age of x = 3*5=15 years Present age of y = 4*5=20 years