Problem: A dragon and knight live on an island. This island has seven poisoned wells, numbered 1 to 7. If you drink from a well, you can only save yourself by drinking from a higher numbered well. Well 7 is located at the top of a high mountain, so only the dragon can reach it.
One day they decide that the island isn't big enough for the two of them, and they have a duel. Each of them brings a glass of water to the duel, they exchange glasses, and drink. After the duel, the knight lives and the dragon dies.
Why did the knight live? Why did the dragon die?
Solution:
showDragon knows that knight cant reach well 7. So he thinks that if i give knight water from well 6 or 7, knight would die for sure. So he would get water from well 6 or 7 for knight.
Knight knew that no matter from which well he gives the water, dragon will go and drink from well 7 and live. So he got normal water for dragon and before duel drank water from well 1.
When they exchanged glasses and drank water, dragon rushed to well 7 and drank poison from it, thinking that it would cure the poison he just drank (but he drank normal water), so dragon died. Knight on the other hand already had poison from well 1 so what dragon gave him effectively cured him. So he lived.
Problem: Now consider that Dragon and Knight are equally intelligent then who is expected to die.
Answer:
Both survive the battle.
Solution:
showAfter the battle, dragon drinks from well 1 in order to guarantee that he is poisoned. He then drinks from well 7 to cure himself. Even if knight gets normal water or poison from well 1-6, dragon is now cured and survives.
As for the knight, he drinks from well 1 before the duel. If dragon has got poison for him then he is cured. But if dragon got normal water then he has to ensure that he cures by drinking poison from higher than well 1. So after the battle, knight re-drinks from well 1. This guarantees that he is poisoned from well 1. Then he goes and drinks from well 2 to cure himself.
So both dragon and knight survive the battle.
The problem wasn't really clear enough for me to have a good chance of answering.
ReplyDeleteKnight made him drink sea water, in turn the dragaon out of suspicion drank water from well 7 only once..so it died
ReplyDeleteBut in the problem, it was not told if the normal water is provided or not
ReplyDelete