Brain Teasers

1. The Doors of Doom

While on the island of Dellzup, you have been captured by the Evil Prince. He has decided to play a game with you. He offers you the choice of two doors, behind one of which lies a hungry lion and behind the other lies treasures beyond your wildest dreams. Guarding one of the doors is a native who always lies and guarding the other door is a native who always tells the truth. Unfortunately, you cannot tell which is which. You may ask one of the natives for help in choosing the door. They both know which door they are guarding, so what single question could you ask?

 

2. Counterfetti

You have 12 coins, one of which is counterfeit. The counterfeit is indistinguishable from the rest except that it is either heavier or lighter (but you don't know which). How can you determine which coin is the counterfeit in 3 weighings on a balance scale?

 

3. Impossible Coins

I have two coins in my pocket that total 35¢. One of the coins is NOT a dime. What are the two coins?

 

4. Which Switch

You are standing outside a room with a closed door.  On the wall beside the door are three power switches, all off.  You want to turn on the lamp inside the room but don't know which switch controls the lamp, and you can't see inside the room with the door closed.  You can't tell if a switch controls anything else.  Assuming that you can flip the switches any way you want, how would you tell which switch controls the lamp after you entered the room?  The catch here is that you only get one try. No going back to reflip the switches after the door has been opened.

 

 

5. Apples & Oranges

You have three boxes, one containing apples, one containing oranges, and one containing apples and oranges. Each box is labelled, one as "apples," one as "oranges," and the last as "apples and oranges." The trouble is that all three boxes are labelled incorrectly! You are allowed to reach into only one box, and pull only one fruit out of it. Whatever the fruit is, you should now be able to label all the boxes correctly! How?

 

6. Socks

Mr. MacGillicuddy owns exactly 24 pairs of socks, 12 pairs white and 12 pairs black. He never sorts them after doing the laundry, figuring it's so easy to just get a pair in the morning, as white and black are easy to tell apart. One night he gets an emergency phone call and has to rush to get dressed and out of the house. On the way to his dresser, the lights go out, and he is left in pitch-black darkness. He wants to look reasonably normally dressed, but cannot see the socks to tell them apart! Being resourceful, he comes up with a solution. He will pull the smallest number of socks from the drawer, get dressed except for socks, and put on a matching pair of socks when he gets into his car and turns on the internal car light. What is the smallest number of socks he can pull out and still guarantee himself of having one matching pair of socks?

 

7. The Missing Dollar

Three men go to a motel and rent a room. The Front Desk clerk charges them $30 for the room. The manager of the motel comes in after the men have settled, and notices that the des clerk has charged the men too much, that the room should only have cost $25.

The manager then goes to the cash drawer and gets five $1 bills, and tells the bellboy take the money back to the three men. On his way up to the room, the bellboy decides that since 5 doesn't divide into 3 evenly at all, that he will give each of the men only one dollar apiece back and keep the other two dollars for himself.

Now that each one of the men has received one dollar back, this means that they only paid $9 apiece for the room. So if they paid a total of $27.00 (9x3=27) and the bellboy kept the other $2, only $29 of the original $30 is accounted for (27+2=29). Where is the other dollar?

 

8. <untitled>

When the day before yesterday was referred to as the day after tomorrow, the day that was then called yesterday was as far away from the day we now call tomorrow as yesterday is from the day which we shall now be able to speak of last Monday as a week ago yesterday. What day is it?

 

The Answers

Answers? What answers?

That, my friends, is the final brain teaser on this page. You didn't think I was just going to GIVE them to you, did you?