This classic was written by Dr Charles Dodgson, aka Lewis Carroll, author of the Alice books.

A captive queen and her son and daughter were shut up in the top room of a very high tower. Outside their window was a pulley with a rope around it, and a basket fastened to each end of the rope of equal weight. They managed to escape with the help of this and a weight they found in the room, quite safely. It would have been dangerous for any of them to come down if they weighed 15 lbs more than the content of the other basket, for they would do so too quick, and they also managed not to weigh less either.

The one basket coming down would naturally of course draw the other basket up.

The queen weighed 195 lbs, daughter 105, son 90, and the weight 75 lbs.

How did they all escape safely?

1. Send the weight crashing down. (The baskets are dangerously unbalanced, but we'll assume that the weight and baskets themselves are indestructable.)

2. Send the son down while the weight comes up.

3. Send the daughter down while the son comes up.

4. Send the weight crashing down.

5. Send the son down while the weight comes up.

6. Send the weight crashing down.

7. Send the the son and daughter up while the queen goes down.

8. Send the weight up and the son down.

9. Send the weight crashing down.

10. Send the son up and the daughter down.

11. Send the weight up and the son down.

12. Since nobody is left at the top to care for the weight, when the son exits the basket the weight will come crashing down.

Alternatively, after step 6 the son and daughter can escape, leaving their wicked step-mother trapped. (Oops! That's a different fairy tale.)

Posted by Jim Lyon on 2002-09-19 06:09:53