Question 237232
Let x = number of years ago 


22-x = age of Zain x years ago
40-x = age of Zain's father x years ago


Father's age WAS 3 times Zain's age
40-x=3(22-x)
40-x = 66-3x


Add +3x to each side:
40-x + 3x = 66-3x+3x
40+2x = 66


Subtract 40 from each side:
2x=26


Divide by 2:
x= 13


Check:  Zain's age was 22-13=9
Father's age was 40-13= 27, which is 3 times Zain's age.


Dr. Robert J. Rapalje