Plep's Puzzles

Monday, January 29, 2007

Camel Race.

A sheikh tells his two sons to race their camels to a distant city to see who will inherit his fortune. The one whose camel is slower will win. The brothers, after wandering aimlessly for days, ask a wise man for advise. After hearing the advice they jump on the camels and race as fast as they can to the city. What does the wise man say?

Tuesday, January 23, 2007

The Idler and the Devil

An idler sighed, 'Everyone says, 'We don't need idlers. You are always in the way. Go to the devil!' But will the devil tell me to get rich?'
No sooner did the idler say this than the devil himself stood in front of him.
'Well', said the devil, 'the work I have for you is light, and you will get rich. Do you see the bridge? Just walk across and I will double the money you have now. In fact, each time you cross I will double your money.'
'You don't say!'
'But there is one small thing. Since I am so generous you must give me $24 after each crossing.'
The idler agreed. He crossed the bridge, stopped to count his money ... a miracle! It had doubled.
He threw $24 to the devil and crossed again. His money doubled, he paid another $24, crossed a third time. Again his money doubled. But now he had only $24, and he had to give it all to the devil. The devil laughed and vanished.
The moral: When anyone gives you advice, you should think before you act.
How much money did the idler start with?

Wednesday, January 17, 2007


Five apples are in a basket. How do you divide the apples among five children so that each child gets an apple, yet one apple remains in the basket?

Thursday, January 11, 2007

A Knight's Tour

A knight is placed on the centre square of a 5 x 5 'chessboard' (or 5 x 5 area of an 8 x 8 chessboard, if you prefer).

Using only the legal moves for a knight in the game of chess, is it possible for the knight to visit every square in the 5 x 5 area?

Monday, January 01, 2007

A contestant on a gameshow is given the choice of three doors.
Behind one door is a speedboat; behind the others, dusty bins.
The contests picks a door.
The host, who knows what's behind the doors, opens another door, which has a dusty bin.
He then says to the contestant, "Do you want to pick the third door or stick with your original choice?"
Is it to the contestant's advantage to switch doors?

Assume the following :-
- The contestant would rather win the speedboard than a dusty bin replica.
- The host is constrained to always open a door with a dusty bin.
- The host is constrained to always make the offer to switch.