A professor of mathematics sent a fax to his wife. It read:
"Dear Wife: You must realize that you are 54 years old, and I
have certain needs which you are no longer able to satisfy. I am
otherwise happy with you as wife, and I sincerely hope you will
not be hurt or offended to learn that by the time you receive
this letter, I will be at the Grand Hotel with my 18-year-old
teaching assistant. I'll be home before midnight. - Your Husband"
When he arrived at the hotel, there was a faxed letter waiting
for him that read as follows:
"Dear Husband: You, too, are 54 years old, and by the time you
receive this letter, I will be at the Breakwater Hotel with the
18- year-old pool boy. Being the brilliant mathematician that
you are, you can easily appreciate the fact that 18 goes into 54
a lot more times than 54 goes into 18. Don't wait up."