Three old women were sitting on a bench outside a nursing home
When an old man walked by.
One of the old women shouted out,
"We bet we can tell exactly how old you are."
The old man said,
"There is no way you can guess it, you old fools."
One of the old women said,
"Sure we can! - Just drop your trousers and under shorts and we can tell your exact age."
Embarrassed a little, but anxious to prove they couldn't do it, he dropped his drawers.
The old women asked him to first turn around a couple of times and to jump up and down several times. Then they all piped up and said,
"You're 87 years old!"
Standing with his trousers and boxers around his ankles, the old gent asked,
"How in the bloody hell did you guess?"
Slapping their knees and grinning from ear to ear, the three old ladies happily shouted in unison...
"We were all at your bloody birthday party yesterday!"