1.
Three people check into a hotel. They pay $30 to the manager and go to their room. The manager finds out that the room rate is $25 and gives $5 to the bellboy to return. On the way to the room the bellboy reasons that $5 would be difficult to share among three people so he pockets $2 and gives $1 to each person. Now each person paid $10 and got back $1. So they paid $9 each, totalling $27. The bellboy has $2, totalling $29.
Where is the remaining dollar?
| |
1.
| |
2.
Ten years from now Tim will be twice as old as Jane was when Mary was nine times as old as Tim. Eight years ago, Mary was half as old as Jane will be when Jane is one year older than Tim will be at the time when Mary will be five times as old as Tim will be two years from now. When Tim was one year old, Mary was three years older than Tim will be when Jane is three times as old as Mary was six years before the time when Jane was half as old as Tim will be when Mary will be ten years older than Mary was when Jane was one-third as old as Tim will be when Mary will be three times as old as she was when Jane was born.
How old are they now?
| |
|
3.
An Arab 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?
| |
|
|
4.
How can a man have mutually safe sex with three women with only two condoms? How can three men have mutually safe sex with one woman with two condoms?
| |
|
5.
Three logicians, A, B, and C, are wearing hats, which they know are either black or white but not all white. A can see the hats of B and C; B can see the hats of A and C; C is blind. Each is asked in turn if they know the color of their own hat. The answers are: A: "No." B: "No." C: "Yes."
What color is C's hat and how does she know?
| |
|
|
6.
You want to send a valuable object to a friend. You have a box which is more than large enough to contain the object. You have several locks with keys. The box has a locking ring which is more than large enough to have a lock attached. But your friend does not have the key to any lock that you have. How do you do it? Note that you cannot send a key in an unlocked box, since it might be copied
| |
|
|
7.
Three humans, one big monkey and two small monkeys are to cross a river: Only humans and the big monkey can row the boat. At all times, the number of human on either side of the river must be GREATER OR EQUAL to the number of monkeys on THAT side. (Or else the humans will be eaten by the monkeys!) The boat only has room for 2 (monkeys or humans) Monkeys can jump out of the boat when it's banked.
| |
|
8.
The moderator takes a set of 8 stamps, 4 red and 4 green, known to the logicians, and loosely affixes two to the forehead of each logician so that each logician can see all the other stamps except those 2 in the moderator's pocket and the two on her own head. He asks them in turn if they know the colors of their own stamps: A: "No" B: "No" C: "No" A: "No B: "Yes"
What are the colors of her stamps, and what is the situation?
| |
|
9.
Three men stand at a fork in the road. One fork leads to Someplaceorother; the other fork leads to Nowheresville. One of these people always answers the truth to any yes/no question which is asked of him. The other always lies when asked any yes/no question. The third person randomly lies and tells the truth. Each man is known to the others, but not to you. What is the least number of yes/no questions you can ask of these men and pick the road to Someplaceorother?
Does the answer change if the third man randomly answers?
| |
|
|
10.
You are given 12 identical-looking coins, one of which is counterfeit and weighs slightly more or less (you don't know which) than the others. You are given a balance scale which lets you put the same number of coins on each side and observe which side (if either) is heavier. How can you identify the counterfeit and tell whether it is heavy or light, in 3 weighings?
| |
|