Currently, I am 9 times as old as my son. Next year, I will be 6 times as old as my son. How old is my son now?
Let your the current age of your son = N
Then your current age = 9N
And in one year we have this relationship
9N + 1 = 6 ( N + 1) simplify
9N + 1 = 6N + 6
9N - 6N = 6 - 1
3N = 5
N = 5/3 = 1 + 2/3 yrs old = 1yr and 8 months old = your son's age now
The son is 1-2/3 years old.
9 times 1-2/3 years is 15 years, i.e., the father's age now.
But the son is over a year old now, which means
the father was at most 14 when his son was born.
