Hi
A father is now three times as old as his son
Let x and 3x represent the ages of the son and father NOW repectively
Question states*** 12years ago...
3x-12 = 6(x-12)
Solving for x
3x-12 = 6x - 72
60 = 3x
20 = x, son's age now. The father is now 60.
CHECKING our Answer***12years ago...
48 = 6*8