logic 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.

## Similar riddles

See also best riddles or new riddles.

logicshortTwo baseball teams played a game. One team won but no man touched base. How could that be?

They were all girl teams.

logicmystery A rich man's son was kidnapped. The ransom note told him to bring a valuable diamond to a phone booth in the middle of a public park. Plainclothes police officers surrounded the park, intending to follow the criminal or his messenger. The rich man arrived at the phone booth and followed instructions but the police were powerless to prevent the diamond from leaving the park and reaching the crafty villain. What did he do?

This is a true story from Taiwan. When the rich man reached the phone booth he found a carrier pigeon in a cage. It had a message attached telling the man to put the diamond in a small bag which was around the pigeon's neck and to release the bird. When the man did this the police were powerless to follow the bird as it returned across the city to its owner.

logic A farmer challenges an engineer, a physicist, and a mathematician to fence off the largest amount of area using the least amount of fence. The engineer made his fence in a circle and said it was the most efficient. The physicist made a long line and said that the length was infinite. Then he said that fencing half of the Earth was the best. The mathematician laughed at the others and with his design, beat the others. What did he do?

cleanlogicThis guy living on the 20th floor in an apartment building got up early each morning to go to work in a downtown store. He always went into the elevator on the 20th floor and rode down to the entrance (1st floor). When he came home he always rode the elevator from the entrance and up to the 8th floor. He walked out of the elevator and walked the stairs up to his apartment on the 20th floor. Why didn't he take the elevator all the way up to his apartment?

This guy is midget and can only reach to the 8th floor button.

logicmathThe owner of a banana plantation has a camel. He wants to transport his 3000 bananas to the market, which is located after the desert. The distance between his banana plantation and the market is about 1000 kilometer. So he decided to take his camel to carry the bananas. The camel can carry at the maximum of 1000 bananas at a time, and it eats one banana for every kilometer it travels.
What is the most bananas you can bring over to your destination?

First of all, the brute-force approach does not work. If the Camel starts by picking up the 1000 bananas and try to reach point B, then he will eat up all the 1000 bananas on the way and there will be no bananas left for him to return to point A.
So we have to take an approach that the Camel drops the bananas in between and then returns to point A to pick up bananas again.
Since there are 3000 bananas and the Camel can only carry 1000 bananas, he will have to make 3 trips to carry them all to any point in between.
When bananas are reduced to 2000 then the Camel can shift them to another point in 2 trips and when the number of bananas left are <= 1000, then he should not return and only move forward.
In the first part, P1, to shift the bananas by 1Km, the Camel will have to
Move forward with 1000 bananas – Will eat up 1 banana in the way forward
Leave 998 banana after 1 km and return with 1 banana – will eat up 1 banana in the way back
Pick up the next 1000 bananas and move forward – Will eat up 1 banana in the way forward
Leave 998 banana after 1 km and return with 1 banana – will eat up 1 banana in the way back
Will carry the last 1000 bananas from point a and move forward – will eat up 1 banana
Note: After point 5 the Camel does not need to return to point A again.
So to shift 3000 bananas by 1km, the Camel will eat up 5 bananas.
After moving to 200 km the Camel would have eaten up 1000 bananas and is now left with 2000 bananas.
Now in the Part P2, the Camel needs to do the following to shift the Bananas by 1km.
Move forward with 1000 bananas – Will eat up 1 banana in the way forward
Leave 998 banana after 1 km and return with 1 banana – will eat up this 1 banana in the way back
Pick up the next 1000 bananas and move forward – Will eat up 1 banana in the way forward
Note: After point 3 the Camel does not need to return to the starting point of P2.
So to shift 2000 bananas by 1km, the Camel will eat up 3 bananas.
After moving to 333 km the camel would have eaten up 1000 bananas and is now left with the last 1000 bananas.
The Camel will actually be able to cover 333.33 km, I have ignored the decimal part because it will not make a difference in this example.
Hence the length of part P2 is 333 Km.
Now, for the last part, P3, the Camel only has to move forward. He has already covered 533 (200+333) out of 1000 km in Parts P1 & P2. Now he has to cover only 467 km and he has 1000 bananas.
He will eat up 467 bananas on the way forward, and at point B the Camel will be left with only 533 Bananas.

logicmathshortThere is a box full of marbles,
all but two are blue,
all but two are green,
and all but two are red.
How many marbles are in the box ?

There are 3 marbles (1 blue, 1 green, and 1 red).

cleanlogic100 men are in a room, each wearing either a white or black hat. Nobody knows the color of his own hat, although everyone can see everyone else's hat. The men are not allowed to communicate with each other at all (and thus nobody will ever be able to figure out the color of his own hat).
The men need to line up against the wall such that all the men with black hats are next to each other, and all the men with white hats are next to each other. How can they do this without communicating? You can assume they came up with a shared strategy before coming into the room.

The men go to stand agains the wall one at a time. If a man goes to stand against the wall and all of the men already against the wall have the same color hat, then he just goes and stands at either end of the line. However, if a man goes to stand against the wall and there are men with both black and white hats already against the wall, he goes and stands between the two men with different colored hats. This will maintain the state that the line contains men with one colored hats on one side, and men with the other colored hats on the other side, and when the last man goes and stands against the wall, we'll still have the desired outcome.

cleanfunnylogicAfter recent events, Question Mark is annoyed with his brother, Skid Mark. Skid thought it would be funny to hide Question's wallet. He told Question that he would get it back if he finds it. So, first off, Skid laid five colored keys in a row. One of them is a key to a room where Skid is hiding Question's wallet. Using the clues, can you determine the order of the keys and which is the right key?
Red: This key is somewhere to the left of the key to the door.
Blue: This key is not at one of the ends.
Green: This key is three spaces away from the key to the door (2 between).
Yellow: This key is next to the key to the door. Orange: This key is in the middle.

The order (from left to right) is Green, Red,Orange, Blue, Yellow. The blue key is the key to the door.

logicYou 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.

logicmysteryscaryOn the first day of the school a young girl was found murdered. Police suspect four male teachers and question them. They were asked what they were doing at 8:00 am.
Mr. Walter: I was driving to school and I was late.
Mr. Thomas: I was checking English exam papers.
Mr. Benjamin: I was reading the newspaper.
Mr. Calvin: I was with my wife in my office.
The police arrested the killer. How did the police find the murderer?

Mr.Thomas as he cannot be checking exam papers on the first day of school.