A professor of maths sent a fax to his wife:

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 a wife,and I sincerely hope you will not be hurt or offended to LEARN that by the time you receive this letter,Ill be at the Grand Hotel with my 18
year old teaching assistant.Ill be home before midnight.

Your Husband.

When he arrives 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 read
this letter,I will be at the Riverside Hotel with the
18 year old pool boy.Since you are a mathematician,you will appreciate that 18 goes into 54 more times than 54 goes into 18.Therefore,dont wait up tonight.

Your Wife.

Nice one,d mugu thot he's wise bt d wife's smarter!

dang!

Brains! Nice one.