Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
1. Trip #1: He takes the cat, leaving the dog and the rat.
He comes back with an empty boat.
2. Trip #2: He takes the rat, leaving the dog alone and the cat on the other shore. When he gets to the other shore, he drops off the rat and takes the cat back with him.
3. Trip #3: He drops off the cat and picks up the dog. He drops the dog off on the other shore with the rat. He returns with an empty boat.
#4 Trip #4: He picks up the cat and returns to the opposite shore where the dog and rat await them.
Okay, how about another logic problem? This one is a little bit tougher:
==========
Three genies are guarding a treasure chest. One of the genies always tells the truth, one always lies, and one randomly tells the truth or lies.
Each of the three genies holds a key of a different color in his hand but they otherwise look alike. One has a key of gold, one of silver, and one of bronze.
The genie with the gold key steps forward and speaks. "I am not the genie of truth." he pauses then adds "The silver key will open the chest."
The genie with the silver key steps forward and speaks. "I am not the genie of lies." he pauses then adds "The bronze key will open the chest."
The genie with the bronze key steps forward and speaks. "I am not the genie who can tell both truth and lies." he pauses then adds "The gold key will open the chest."
Which key will open the chest?
The gold key.
The first genie, with the gold key, is the genie of truth and lies. Why?
The genie with the gold key steps forward and speaks. "I am not the genie of truth." he pauses then adds "The silver key will open the chest."
The genie cannot be the genie of truth, or he would truthfully say he is so.
The genie must be either the genie of lies or the genie of lie/truth.
If he is the genie of lies, he cannot say he is not the genie of truth because it would be a true statement, and this genie always lies.
Therefore, this genie is the genie of truth and lies.
The second genie, with the silver key, is the genie of lies.
We have established already that he is either the genie of truth or the genie of lies because Gold Genie is the genie of truth/lies.
The genie with the silver key steps forward and speaks. "I am not the genie of lies." he pauses then adds "The bronze key will open the chest."
This genie is either the Genie of Truth or the Genie of Lies. If he is the Genie of Lies, he can say no other thing EXCEPT that he is not the genie of lies or that he is not the genie of lie/truth. We already know who the genie of lie/truth is (the gold genie); therefore, the silver-key genie is the Genie of Lies.
By process of elimination, the third genie, the one with the bronze key, is the Genie of Truth, and the gold key opens the box.
Very nice, though I solved it a little differently.
Once you realize that the genie with the gold key is the genie of truth/lies, you can skip to the genie with the bronze key.
Since he says he is not the genie of truth/lies, he has to be telling the truth since you can confirm that fact. So, you know that he is the genie of truth and his statement about the key is correct.
=========
Anyhow, I will put up one more logic problem, then it is time for someone else to post a problem.
Here goes:
A wealthy merchant accidentally releases a genie from its bottle. Once freed, the genie quickly examines the merchant's shop for a means by which to gain its revenge.
It quickly locates the merchant's stash of gold and hides it in a large clay jar.
The genie then conjures 8 more identical pots and places identical weights within each of them, then fills all 9 pots the pots up to the brim with sand and seals them up using its magic. It then mixes them up so the merchant loses track of which pot contains his gold.
Next the genie conjures a large balancing scale (the kind with two baskets on a pivot point.)
Finally the genie speaks. "Eight of these jars now weigh the same. The one with your coin inside weighs different, though I will not say whether it weighs more or less."
The genie laughs at the merchant.
"You may use the scales as many as three times if you wish, and you may select a single pot which will be returned to you. The others I will take for myself."
The merchant finds that he can not determine which jar is which simply by lifting them and he is unable to open or break the pots. They all feel roughly the same to his arms.
How can the merchant solve the genie's challenge and determine which pot contains his life savings?
Very nice, though I solved it a little differently.
Once you realize that the genie with the gold key is the genie of truth/lies, you can skip to the genie with the bronze key.
Since he says he is not the genie of truth/lies, he has to be telling the truth since you can confirm that fact. So, you know that he is the genie of truth and his statement about the key is correct.
=========
Anyhow, I will put up one more logic problem, then it is time for someone else to post a problem.
Here goes:
A wealthy merchant accidentally releases a genie from its bottle. Once freed, the genie quickly examines the merchant's shop for a means by which to gain its revenge.
It quickly locates the merchant's stash of gold and hides it in a large clay jar.
The genie then conjures 8 more identical pots and places identical weights within each of them, then fills all 9 pots the pots up to the brim with sand and seals them up using its magic. It then mixes them up so the merchant loses track of which pot contains his gold.
Next the genie conjures a large balancing scale (the kind with two baskets on a pivot point.)
Finally the genie speaks. "Eight of these jars now weigh the same. The one with your coin inside weighs different, though I will not say whether it weighs more or less."
The genie laughs at the merchant.
"You may use the scales as many as three times if you wish, and you may select a single pot which will be returned to you. The others I will take for myself."
The merchant finds that he can not determine which jar is which simply by lifting them and he is unable to open or break the pots. They all feel roughly the same to his arms.
How can the merchant solve the genie's challenge and determine which pot contains his life savings?
Take any 2 jars and weigh them against each other. If they are the same weight, keep weighing one of the jars against all the others until you find 2 jars that weigh different amounts. Put these 2 jars aside. Then put 4 of the identical jars on 1 side of the scale and the other 3 identical jars on the other side. Now put 1 of the 2 jars on the scale. If it balances the scale, then the jar you have left is the one w/the gold. Likewise, if the scale is not balanced, then the jar w/the gold is the one you just placed on the scale.
Take any 2 jars and weigh them against each other. If they are the same weight, keep weighing one of the jars against all the others until you find 2 jars that weigh different amounts. Put these 2 jars aside. Then put 4 of the identical jars on 1 side of the scale and the other 3 identical jars on the other side. Now put 1 of the 2 jars on the scale. If it balances the scale, then the jar you have left is the one w/the gold. Likewise, if the scale is not balanced, then the jar w/the gold is the one you just placed on the scale.
According to the rules of the puzzle:
Quote:
"You may use the scales as many as three times if you wish...
The method you describe can take more than 3 weighings.
Google "Richard Gere" and "Gerbil". It's an urban legend but you will get the idea.
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.
Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
I give up ... can anyone lend a hand?
