54 Year old accountant leaves a letter for his wife

A 54 year old accountant leaves a letter for his wife
one Friday evening and read's: Dear Wife (that's what
he called her) I am 54 and by the time you receive this
letter I will be at the Grand Hotel with my beautiful
and sexy 18 year old secretary. When he arrived at the
hotel there was a letter waiting for him as follows:
Dear Husband (that's what she called him) I too am 54
and by the time you receive this letter I will be at
the Hilton Hotel with my handsome and virile 18 year
old toy boy. You being an accountant will therefore
appreciate that 18 goes into 54 many many more times
than 54 goes into 18!!!!