Birthday Riddle
Probability
Level
1
On his birthday, a father comes up with the following riddle:
"I'm the father of two teenagers. My age today is three times my daughter's. If I add 4 to my age, now it becomes 4 times my son's age."
How old is the father?
The answer is 48.
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1 solution
The thing is I did come up with this riddle the day of my 48th birthday! The solution is easy to find by trial. The following table shows all possible values for the father's age, including the only one that matches the statement (48), being my daughter's age 16 and my son's, 13. (Real ages at the time, by the way!)