At one point in time, their ages were: M = 30; B = x; K = 2x. (Kenny was twice Bala's age when Mike was 30).
At another point in time, their ages were: M = 2y; B = 21; K = y. (Mike was twice Kenny's age when Bala was 21).
The number of years between those two times is the same for each of them:
30-2y = x-21 = 2x-y
30-2y = x-21 --> x+2y = 51; x-21 = 2x-y --> y-x = 21
x+2y = 51 and y-x = 21 --> 3y = 72 --> y = 24
So Mike was 48 and Kenny was 24 when Bala was 21.
So the difference between Mike's age and Bala's age is 27 years.
So when Mike is 62, Bala will be 35.