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?
Let the son, having weight 90 lbs, be denoted by S-90
The daughter weighing 105 lbs, be denoted by D-105
The queen, weighing 195 lbs, be denoted by Q-195.
The weight (75 lbs) is denoted by W-75
Then, the successful escape can be achieved by the following manner:
Step 1: The weight goes down and the empty basket comes out.
Step 2: S-90 goes down and W-75 comes up.
Step 3: W-75 is put aside. D-105 goes down and S-90 comes up.
Step 4: S-90 alights from the basket. W-75 goes down and the empty basket comes up.
Step 5: Q-195 goes down, D-105 and S-90 together come up. D-90 alights from the basket.
Step 6: W-75 goes down, empty basket comes up.
Step 7: S-90 goes down, W-75 comes up.
Step 8: D-105 takes out W-75 and she goes down, S-90 comes up.
Step 9: S-90 alights fro basket and he sends down W-75, empty basket comes up.
Step 10: S-90 goes down, W-75 comes up.
Step 11: S-90 gets out of the basket, W-75 falls down to the ground.
Edited on July 18, 2022, 12:24 am