Medium riddles

logic

Hardware store in Boston

Fred went to a hardware store in Boston with Alex, Ben, and George. He noted that a hammer cost ten times as much as a screwdriver and a power saw cost ten times as much as a hammer. The storekeeper said that Ben could buy a power saw, George could buy a screwdriver and Alex could buy a hammer. Based on this what would the storekeeper let Fred buy? Alex's full name is Alexander and Ben's full name is Benjamin. George was Alex's boss and good friend.
Fred could buy all three (the power saw, hammer and screw driver) since he had $111 with him (a $1 bill - George Washington, a $10 Alexander Hamilton, and a $100 bill - Ben Franklin). Boston is in the USA and therefore uses the US currency I just described.
93.39 %
38 votes

logicshort

The rarest book in the World

A man had a book that was worth $40,000. There were only 2 books in existence. He threw it in the furnace, reducing it to a pile of soot. Why did he do this?
He destroyed the book because he has two, and by only having one, the value goes up.
93.39 %
38 votes

interviewlogic

Mislabeled Jar Puzzle

You have 3 jars that are all mislabeled. One jar contains Apple, another contains Oranges and the third jar contains a mixture of both Apple and Oranges. You are allowed to pick as many fruits as you want from each jar to fix the labels on the jars. What is the minimum number of fruits that you have to pick and from which jars to correctly label them?
Let’s take a scenario. Suppose you pick from jar labelled as Apple and Oranges and you got Apple from it. That means that jar should be Apple as it is incorrectly labelled. So it has to be Apple jar. Now the jar labelled Oranges has to be Mixed as it cannot be the Oranges jar as they are wrongly labelled and the jar labelled Apple has to be Oranges. Similar scenario applies if it’s a Oranges taken out from the jar labelled as Apple and Oranges. So you need to pick just one fruit from the jar labelled as Apple and Oranges to correctly label the jars.
93.05 %
36 votes

funny

The doughnut shop

Why did the doughnut shop close?
The owner got tired of the (w)hole business!
92.86 %
35 votes

dirty

Murdered wife

A man murders his wife with a knife in their car. Nobody is around to see this. He throws her out of the car being careful not to leave any fingerprints on her body. Next he throws the knife off of a cliff into a gorge where it will never be found and he goes home. An hour later the police call him and tell him that his wife has been murdered and he needs to come to the scene of the crime immediately. As soon as he arrives, he is arrested.
He never ask the cop where the scene of the crime was so they knew that he had murdered his wife.
91.77 %
30 votes

logic

Prisoner sentenced to death

You are a prisoner sentenced to death. The Emperor offers you a chance to live by playing a simple game. He gives you 50 black marbles, 50 white marbles and 2 empty bowls. He then says, "Divide these 100 marbles into these 2 bowls. You can divide them any way you like as long as you use all the marbles. Then I will blindfold you and mix the bowls around. You then can choose one bowl and remove ONE marble. If the marble is WHITE you will live, but if the marble is BLACK... you will die." How do you divide the marbles up so that you have the greatest probability of choosing a WHITE marble? HINT: The answer does not guarantee 100% you will chose a white marble, but you have a much better chance.
Place 1 white marble in the bowl, and place the rest of the marbles in the other bowl (49 whites, and 50 blacks). This way you begin a 50/50 chance of choosing the bowl with just one white marble, therefore life! BUT even if you choose the other bowl, you still have almost a 50/50 chance at picking one of the 49 white marbles.
90.47 %
44 votes

logicmath

Tiling Without Corners

You can easily "tile" an 8x8 chessboard with 32 2x1 tiles, meaning that you can place these 32 tiles on the board and cover every square. But if you take away two opposite corners from the chessboard, it becomes impossible to tile this new 62-square board. Can you explain why tiling this board isn't possible?
Color in the chessboard, alternating with red and blue tiles. Then color all of your tiles half red and half blue. Whenever you place a tile down, you can always make it so that the red part of the tile is on a red square and the blue part of the tile is on the blue square. Since you'll need to place 31 tiles on the board (to cover the 62 squares), you would have to be able to cover 31 red squares and 31 blue squares. But when you took away the two corners, you can see that you are taking away two red spaces, leaving 30 red squares and 32 blue squares. There is no way to cover 30 red squares and 32 blue squares with the 31 tiles, since these tiles can only cover 31 red squares and 31 blue squares, and thus, tiling this board is not possible.
90.26 %
43 votes