Some years ago, there was a Mensa convention in San Francisco. Mensa, as you may know, is an international organisation for people who have an IQ of 140 or higher.
Several of the Mensa members went out for lunch at a local cafe.
When they sat down, one of them discovered that their salt mill contained pepper, and their pepper mill was full of salt.
How could they swap the contents of the two bottles without spilling any and using only the implements at hand?
Clearly, this was a job for Mensa minds!
The group debated the problem and presented ideas and finally, came up with a brilliant solution involving a napkin, a straw and an empty saucer.
They called the waitress over, ready to dazzle her with their solution
“Miss,” they said, “we couldn’t help but notice that the pepper mill contains salt and the salt shaker contains …”
But before they could finish their sentence, the waitress interrupted, “Oh, sorry about that.”
And as she said those words, she leaned over the table, unscrewed the caps of both bottles and switched them.
All that could be heard was dead silence at the Mensa table.