web math problem

Futility Closet:

Thursday, February 16, 2006
A mother is 21 years older than her son. Six years from now, she will be five times his age. Where’s the father?
I won’t give the answer to this one — if you do the math, you’ll know precisely where he is.


I must say, after having it take 3 pieces of paper and a wrong assumption to figure out, that that’s a dirty math problem.