Sample Puzzles for Competitions

January 1, 2008

General Gasslefield, accused of high treason, is sentenced to death by the court-martial. He is allowed to make a final statement, after which he will be shot if the statement is false or will be hung if the statement is true. Gasslefield makes his final statement and is released. What could he have said?

General Gasslefield said: "I will be shot." If this statement was true, he would have been hung and thus not be shot. But then his statement would be false, which implies that he should be shot, making the statement true again, etc… In other words: the verdict of the court-martial could not be executed and the general was released..

A long, long time ago, two Egyptian camel drivers were fighting for the hand of the daughter of the sheik of Abbudzjabbu. The sheik, who liked neither of these men to become the future husband of his daughter, came up with a clever plan: a race would determine who of the two men would be allowed to marry his daughter. And so the sheik organized a camel race. Both camel drivers had to travel from Cairo to Abbudzjabbu, and the one whose camel would arrive last in Abbudzjabbu, would be allowed to marry the sheik's daughter. The two camel drivers, realizing that this could become a rather lengthy expedition, finally decided to consult the Wise Man of their village. Arrived there, they explained him the situation, upon which the Wise Man raised his cane and spoke four wise words. Relieved, the two camel drivers left his tent: they were ready for the contest! Which 4 wise words did the Wise Man speak?

Take each other's camel..

A boy leaves home in the morning to go to school. At the moment he leaves the house he looks at the clock in the mirror. The clock has no number indication and for this reason the boy makes a mistake in interpreting the time (mirror-image). Just assuming the clock must be out of order, the boy cycles to school, where he arrives after twenty minutes. At that moment the clock at school shows a time that is two and a half hours later than the time that the boy saw on the clock at home. At what time did he reach school?

The difference between the real time and the time of the mirror image is two hours and ten minutes (two and a half hours, minus the twenty minutes of cycling). Therefore, the original time on the clock at home that morning could only have been five minutes past seven: The difference between these clocks is exactly 2 hours and ten minutes (note that also five minutes past one can be mirrored in a similar way, but this is not in the morning!).Conclusion: The boy reaches school at five minutes past seven plus twenty minutes of cycling, which is twenty-five minutes past seven!.

In front of you are 10 bags, filled with marbles. The number of marbles in each bag differs, but all bags contain ten marbles or more. Nine of the ten bags only contain marbles of 10 grams each. One bag only contains marbles of 9 grams. In addition, you have a balance which can weigh in grams accurate, and you are allowed to use it only once (i.e. weigh a single time). How can you find out in one weighing, which bag contains the marbles of 9 grams?

Number the ten bags from 1 up to and including 10. Then take one marble from bag 1, two marbles from bag 2, three marbles from bag 3, etc. Place all 55 marbles that you selected from the bags together on the balance. The number of grams that the total weight of these 55 marbles differs from 550 grams, is equal to the number of marbles of 9 grams that are among those 55 marbles, and that is equal to the number of the bag which contains the marbles of 9 grams.

An old farmer died and left 17 cows to his three sons. In his will, the farmer stated that his oldest son should get 1/2, his middle son should get 1/3, and his youngest son should get 1/9 of all the cows. The sons, who did not want to end up with half cows, sat for days trying to figure out how many cows each of them should get. One day, their neighbour came by to see how they were doing after their father's death. The three sons told him their problem. After thinking for a while, the neighbour said: "I'll be right back!" He went away, and when he came back, the three sons could divide the cows according to their father's will, and in such a way that each of them got a whole number of cows. What was the neighbour's solution?

The neighbour borrowed an extra cow, to make the total number of cows 18. Then the oldest son got 1/2 of 18 is 9 cows, the middle son got 1/3 of 18 is 6 cows, and the youngest son got 1/9 of 18 is 2 cows. Since 9+6+2 = 17, the cows could be divided among the three brothers in such a way that the borrowed cow was left over, and could be returned to its owner..

It's always 1 to 6, it's always 15 to 20, it's always 5, but it's never 21, unless it's flying. What is this?

The answer is: a dice. An explanation:

"It's always 1 to 6″: the numbers on the faces of the dice,

"it's always 15 to 20″: the sum of the exposed faces when the dice comes to rest after being thrown,

"it's always 5″: the number of exposed faces when the dice is at rest,

"but it's never 21″: the sum of the exposed faces is never 21 when the dice is at rest,

"unless it's flying": the sum of all exposed faces when the dice is flying is 21 (1 + 2 + 3 + 4 + 5 + 6)..

A man has a wolf, a goat, and a cabbage. He must cross a river with the two animals and the cabbage. There is a small rowing-boat, in which he can take only one thing with him at a time. If, however, the wolf and the goat are left alone, the wolf will eat the goat. If the goat and the cabbage are left alone, the goat will eat the cabbage. How can the man get across the river with the two animals and the cabbage?

There are two solutions:

First, the man takes the goat across, leaving the wolf with the cabbage. Then he goes back. Next, he takes the wolf across. Then the man goes back, taking the goat with him. After this, he takes the cabbage across. Then he goes back again, leaving the wolf with the cabbage. Finally, he takes the goat across.

First, the man takes the goat across, leaving the wolf with the cabbage. Then he goes back. Next, he takes the cabbage across. Then the man goes back, taking the goat with him. After this, he takes the wolf across. Then he goes back again, leaving the wolf with the cabbage. Finally, he takes the goat across. .

## Sunday, May 18, 2008

### Puzzles Campus Placement

Posted by msnprabu at 12:52 AM

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