@SqSehrish there are three answers: 60 and 6; 51 and 15; and 42 and 24. There are no non-integer answers. The statement of the problem tells us that the digits must add up to 6. Also have to assume that Father is older than son.
@zohi_4125 2 possible answers:
If the given equations are EXAMPLES of the relationship, the answer is 9.
If the given equations are in a sequence, then the answer is 18.
@speedofetish_mt Those are magnificent! What brand are they? I would wear them to a club. I might even wear them hard if I had already wearing something else hard. Dicks are designed to be shown off!