Question 321209
Let x=Babu's age now

y=son's age now

Presently, Babu is 3 times his sons age: x=3y

10 years ago he was 5 times his age: x-10=5(y-10)

3y-10=5y-50

2y=40

y=20

His son his 20, and since his father (Babu) is 3 times that, he is 60.

Check. 10 years ago Babu would have been 50 and his son 10. 50 is 5 times 10.

Check!