Question 635677
Let
Present age of of Father = f years old
Present age of Son = s years old

Father is 3 times as old as his son
f=3s...............(1)
12 years ago
father was = f-12 years old
Son was = s-12 years old
Then
f-12=6(s-12)
f-12=6s-72
f=6s-72+12
f=6s-60..............(2)
Compare (1) and (2)
3s=6s-60
3s-6s=-60
-3s=-60
-3s/-3=-60/-3
s=20
Put the value of s in (1)
f=3s
f=3(20)
f=60

Present age of of Father = f = 60 years old
Present age of Son = s = 20 years old