ELEMENTRY MATHS

I hadn't a clue what to blip tonight but I detected that this would suffice my dear Watson.

Sherlock Holmes and Dr. Watson are taking a trip across a desert by hot-air balloon. There are not many landmarks; so eventually, they become lost. Luckily, while flying quite low, they see a man.

Holmes shouts, "Sir, could you please tell me where we are?"

The man looks up, ponders for a moment, and then answers, "Gentlemen, you are in a hot-air balloon!"

At this moment, a burst of wind picks up the balloon and carries it away.

Holmes turns to Watson and asks: "My friend, do you know who that man is?"

"No, Holmes, of course not!"

"He's a mathematician!"

"Holmes, that's incredible! But *how* do you know?"

"It's very simple, Watson. First of all, the man thought before giving us an answer. Secondly, his answer was absolutely correct. And thirdly, the answer he gave us was of no practical use, whatsoever!"