Question 498252
Let 
Current age of Max=m
Current age of his son=s

Eleven years ago means we have to subtract 11 from their current ages
m-11=s-11
Then
Max was three times as old as his son
m-11=3(s-11)
m-11=3s-33
m=3s-33+11
m=3s-22 ..........(1)
Three years from now means we have to add 3 to their current ages
m+3=s+3
Then Max will be twice as old as his son
m+3=2(s+3)
m+3=2s+6
m=2s+6-3
m=2s+3..........(2)
Put the value of m from (1) to (2)
3s-22=2s+3
3s-2s=3+22
s=25
Put the value of s in (1) or (2)
m=2(25)+3..........(2)
m=50+3
m=53
Max is 53 and his son is 25