01. You are given two threads which takes 1hour to burn from one end to the other. Using these 2 threads and a matchbox(or lighter) how will you measure 45 minutes You are not allowed to break these threads.
02. A man is condemned to death. He is given to say a last statement; if it is truth he is hanged to death and if it is false he is poisoned. He uttered his last sentence from which he escaped. What is the last statement ?
03. There are 3 settlers and 3 Indians on one side of the creek. How can you get them all over to the other side by using a boat that holds two(they can only get there by boat). You can never have more Indians than settlers on one side at a time because the Indians will kill the settler.
04. There are 4 people that need to cross a bridge. Only two can go across at a time and one has to come back with the flashlight each time. They take 1 minute, 2 minutes, 4 minutes and 5 minutes. They only walk as fast as the slowest one. They are able to all cross the bridge in 12 minutes. How?
05. X number of cards are placed on table A. Out of X, Y number of them are face down.You have to move cards (one at a time) from table A to table B. After the move both tables should have equal number of cards face down. You are blind folded and sit in the middle of table A and table B.(means you can touch the cards but you cannot see whether they are face up or down) You are given the values of X and Y. How do you accomplish this ?
06. In a 3 way junction there is a house in which there are 2 brothers. Elder one always tell the TRUTH and the younger one always LIE. Here a man comes from one road and wanted to go for a particular city (say city A) and he don't know which way to take out of the two. He knows that in that house there are 2 brothers who always made TRUE and FALSE statements but he do not know who is who. At one time there is one one brother at home. The traveller asks only one question from one of the brothers who is there at that moment and chooses the correct way for his destination. What is that question and whats the road he chooses ?
07. A warden of a prison comes back to the prison from a party very drunk. In his state, he accidentally turns the key to open all 100 of the jail cells.He realizes what he's done, so he goes back and turns the key on every other cell (thus, now cell 1 is open, cell 2 is closed, cell three is open, etc.). He realizes that he hasn't closed all of them, so he goes back and turns the key on every third cell (thus, now cell 3 is closed, and cell 6, which he closed when he turned every other key, is now open). Still drunk, he goes back and turns the key on every 4th, then every 5th, 6th, 7th, etc. until he turns the key on every 100th cell (thus, only on cell #100). After all this,which cells remain open?
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ANSWERS:
01. Burn both ends of one thread and one end of the other. After the first thread is burnt completely burn the other end of the second thread. The total time taken by threads to burn will be 45 minutes.
02."I should be poisoned" think a bit and analyze. Still if you don't get keep on reading.
Explanation : If "I should be poisoned" is TRUE(by sentence) you have to poison him. But according to the rule of the riddle "He should be hanged". Because of the contradiction no one can hang him or poison him. This solves by CONTRADICTION.
03. Any number could be ended in four which always has four letters only.
04. 1 & 2 : 2mins,
1 back : 1min,
4 & 5 : 5mins,
2 back : 2mins,
1 & 2 : 2mins
Total= 2+1+5+2+2= 12mins
05. Pick a card from table A , flip the side and place on table B. You do this until you reach Y.
06. "If your brother is here instead of you what would he say for the question "What is the correct way to city A" ? " Then he chooses the other road whatever the brother say.
07. All the cells that are perfect squares (1,4,9,16,25,36,49,64,81,100) remain open because they have an odd number of multiples so the key will be turned an odd number of times on them, making them open at the end. All others have an even number of multiples and will stay closed.
