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

what am I

Don't cut me in half, you get nothing

Turn me on my side and I am everything. Cut me in half and I am nothing. What am I?
The number 8. On it's side is infinity, cut the symbol in half, you get two zeros.
93.22 %
37 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.
92.25 %
32 votes

logicmath

Flipping Lockers

There are 1 million closed school lockers in a row, labeled 1 through 1,000,000. You first go through and flip every locker open. Then you go through and flip every other locker (locker 2, 4, 6, etc...). When you're done, all the even-numbered lockers are closed. You then go through and flip every third locker (3, 6, 9, etc...). "Flipping" mean you open it if it's closed, and close it if it's open. For example, as you go through this time, you close locker 3 (because it was still open after the previous run through), but you open locker 6, since you had closed it in the previous run through. Then you go through and flip every fourth locker (4, 8, 12, etc...), then every fifth locker (5, 10, 15, etc...), then every sixth locker (6, 12, 18, etc...) and so on. At the end, you're going through and flipping every 999,998th locker (which is just locker 999,998), then every 999,999th locker (which is just locker 999,999), and finally, every 1,000,000th locker (which is just locker 1,000,000). At the end of this, is locker 1,000,000 open or closed?
Locker 1,000,000 will be open. If you think about it, the number of times that each locker is flipped is equal to the number of factors it has. For example, locker 12 has factors 1, 2, 3, 4, 6, and 12, and will thus be flipped 6 times (it will end be flipped when you flip every one, every 2nd, every 3rd, every 4th, every 6th, and every 12th locker). It will end up closed, since flipping an even number of times will return it to its starting position. You can see that if a locker number has an even number of factors, it will end up closed. If it has an odd number of factors, it will end up open. As it turns out, the only types of numbers that have an odd number of factors are squares. This is because factors come in pairs, and for squares, one of those pairs is the square root, which is duplicated and thus doesn't count twice as a factor. For example, 12's factors are 1 x 12, 2 x 6, and 3 x 4 (6 total factors). On the other hand, 16's factors are 1 x 16, 2 x 8, and 4 x 4 (5 total factors). So lockers 1, 4, 9, 16, 25, etc... will all be open. Since 1,000,000 is a square number (1000 x 1000), it will be open as well.
91.39 %
49 votes

logicshort

The mystery of Cindy

The day before yesterday Cindy was 17. Next year she will be 20. How can this be?
The statement was made on January 1. Cindy's birthday is on December 31. She was 17 the day before yesterday (Dec 30). She was 18 yesterday. She will be 19 this year (Dec 31) and 20 next year.
91.39 %
49 votes

short

Five fingers

What has five finger but is not alive?
A glove.
91.24 %
28 votes