The sum of ages of A and B is 50 years. A said to B, “I am twice as old as you were when I was as old as you are. Find the present age of B.
20
Let age of A = x years
Let age of B = y years
Difference of their ages = (x - y) years
According to given condition
y = 2 [y - (x - y)]
y = 2 (y - x + y)
y = 2 (2y - x)
y = 4y - 2x
2x = 3y ..............(i)
According to second condition
x + y = 50
x = 50 - y ............(ii)
Solving (i) and (ii) we get
y = 20
Therefore B s age is 20 yrs