Brain Teasers

Black, White, and Brown


Played 11813 Times
Doctor Alex White of the oncology department, Doctor Taylor Black of pediatrics, and Robin Brown, a young nurse, were having coffee together. "Isn't it odd," the lady observed, "that our last names are White, Black, and Brown and that one of has black hair, one white hair, and one brown." "Yes!" said the person with black hair, "and notice that not one of us has hair that matches his or her name!" "You're right!" exclaimed Doctor White. If the lady's hair is not brown, what is the color of Doctor Black's hair?

Crossed Out Letters


Played 11633 Times
Cross out nine letters from the letters below so that the remaining letters spell a single word: N A I S N I E N L G E L T E T W E O R R S D

Odd One Out


Played 11417 Times
If there are 2 identical boxes, one weighing more than the other, you can easily identify the heavier one by placing them on opposite pans of a balance scale. What if there are 9 identical boxes, one of which weighing more than the others. How many weighings must be done to identify the heavier box?

The Flight Around the World


Played 11610 Times
There are a group of airplanes on an island. The tank of each airplane contains just enough fuel to fly halfway around the world. Any amount of fuel can be transferred from one plane to another while in the air. The only fuel source is on the island. It is assumed that all planes burn fuel at the same rate and fly at the same speed. What is the smallest number of airplanes needed to ensure the complete flight of one plane around the world? All planes should return safely to the island.

The Commuter Riddle


Played 11552 Times
Adam, a regular commuter, arrives at the train station at five oclock every evening, where his wife meets him and drives him home. One day, Adam takes an earlier train and arrives at the station at four. Instead of calling his wife, he decides to walk home along the route his wife usually takes. They meet somewhere along the way and they drive home, arriving 10 minutes earlier than usual. Let us say that the wife drives at a constant speed and always leaves just in time to meet the five oclock train, how long did Adam walk before his wife picked him up?

Brother vs. Sister


Played 11433 Times
John has two siblings, a brother and a sister, whom he both loves very much. Every Saturday, he takes the subway to visit one of them. To visit his brother, John takes a train on the downtown side of the platform. To visit his sister, he takes a train on the uptown side of the platform. He likes both his siblings equally well, so he simply takes whichever train first comes along. He arrives at the platform at a random time each Saturday. Both trains arrive at the station equally often every 10 minutes. However, John realized that he has been spending more time with his brother than his sister (9 times out of 10). Why do the odds favor John's brother so much?

The Wooden Cube Riddle


Played 11659 Times
A carpenter wants to saw a wooden cube that measures three inches on each side into 27 one-inch cubes. This can be done by making six cuts through the cube, keeping the pieces in their original position. Is there a way to reduce the number of cuts by rearranging the pieces after each cut?

The 100-Yard Race


Played 11572 Times
Annie and Amy race each other for a distance of 100 yards. Annie wins by 10 yards. They decide to try again, but to even things up, Annie begins 10 yards behind the starting line. If they both run at the same speed they did earlier, who will win the race?

The Interrupted Card Game


Played 11568 Times
You are about to play a game of bridge with some friends when the phone rings as you dealing the cards. You leave to answer the phone, but when you return, no one can remember where the last card was dealt. Without counting any of the cards, how can you finish the deal correctly?

The Fork in the Road


Played 11872 Times
A traveler finds himself on an island inhabited by two opposing tribes. Members of one tribe must always tell the truth, while members of the other always lie. He comes to a fork in the road and has to ask a bystander which path he should take to reach a nearby village. The traveler has no way of finding out whether the bystander is a liar or a truth teller. What question should he ask to determine which path to take?

The Identical Bolts Riddle


Played 11604 Times
There are two identical bolts that have been placed together so that their grooves fit into each other. If you move the bolts around each other while firmly holding the head so they do not rotate, will they: a. move inward, b. move outward, or c. remain the same distance from each other?

The Counterfeit Coins Riddle


Played 11957 Times
There are 10 stacks of coins. Each stack contains 10 coins of the same value. However, one of the stacks is made entirely of counterfeit coins. You know that one counterfeit coin weighs one gram more than a genuine coin, and you know how much a genuine coin should weigh. You can weigh the coins on a pointer scale. What is the smallest number of weighings needed to identify the counterfeit stack? Explain.

The Mislabeled Boxes Riddle


Played 12350 Times
There are three boxes. One contains 2 black marbles, one contains 2 white marbles, and one contains 1 black marble and 1 white marble. The boxes are labeled BB, WW, and BW. However, each box is labeled incorrectly. You may take one marble at a time out of any box, but you are not allowed to look inside. What is the quickest way to determine the contents of each box?

The Broken Chessboard Riddle


Played 11918 Times
You have a chessboard and 32 dominoes. Each domino can cover two adjacent squares on the chessboard. Therefore, the 32 dominoes can cover all 64 squares on the board. If you cut out two squares at diagonally opposite corners of the chessboard and throw out one of the dominoes, is it possible to arrange the 31 dominoes on the board so that the 62 remaining squares are covered? Explain.

Draw Poker Riddle


Played 12350 Times
Two men are playing draw poker with a standard 52-card deck. They spread the deck face up on the table so that both players can see all the cards. Player 1 draws a hand by choosing any five cards he wants. Player 2 does the same. Now, Player 1 can either keep the hand he has or draw up to 5 cards. Player 2 can do the same. The player with the better hand wins. Rules: - Cards that are discarded by a player are no longer part of the game. - All the suits are equal in value, so a flush will tie with another flush unless one has higher cards. After a few rounds, the players realize that Player 1 can always win if he draws a certain hand on his first turn. What hand should this be?

The Hunter


Played 11973 Times
There's a famous riddle about a hunter who walks one mile south, one mile east, and one mile north and ends up right back where he started. He sees a bear and shoots it. What color is the bear? The accepted answer is white; the hunter is at the North Pole and the bear is a polar bear. However, someone recently discovered that the North Pole isn't the only starting point that can meet those conditions. Name another spot on the globe from which a person can walk one mile south, one mile east, and one mile north and still find himself right back at his starting point.

Age Riddle


Played 11701 Times
The day before yesterday Johny was 5. next year he'll be 8. Explain..

Crows On Fence


Played 11864 Times
There are 4 crows on a fence. A farmer shoots one crow. How many crows are left on the fence?

Horse Riding Tuesday Riddle


Played 12128 Times
A man rides into town on Tuesday. Two days later he leaves on Sunday. How is this possible?

Little Indian and Big Indian Riddle


Played 15131 Times
Little indian and big indian are walking side by side. Big indian is the father of little indian, but little indian isn't the son of the big indian. How is this possible?

Three Consecutive Double Letters Riddle


Played 12774 Times
What word has three consecutive double letters in a row. i.e. balloon has two consecutive double letters in a row. "ll' and "oo".

Balloon In Car Riddle


Played 12465 Times
There is a helium balloon in the middle of your car touching the ceiling. The car is at a stop and the car quickly accelerates. What happens the balloon?

2 Goats Million Dollars Door Riddle


Played 12496 Times
You are on a gameshow. The gameshow host tells you there are three doors. Behind two of the doors are a goat and behind one of the doors is a million dollars. He tells you he will reveal a different door after you make you selection. You pick one door and he then opens a different door to reveal a goat. He then offers you the option to switch doors. Should you change the door you picked? Keep it. Or does it not matter?

Boy or Girl Riddle


Played 12277 Times
You ask your friend Gillian has two children. You ask Gillian whether at least one them is a boy. She responds yes. Assuming the chance her having a boy and girl is 50/50. What is the chance that she has 2 boys? 1 in ?

Summer Riddle


Played 12268 Times
Gerry birthday is Dec 24th. But his birthday always fall in Summer. How is this possible?

Kids Name Riddle


Played 12169 Times
Gavin's Mother has three kids. The first child's name is Adam. The second child's name is Eve. What is the third child's name?

Three Women Riddle


Played 12224 Times
Jane is looking at Martha and Martha is looking at Elizabeth. Jane is married and Elizabeth is not married. Is a married person looking a non-married person? 1. Yes 2. No 3. Cannot tell with the information given

Rope Burning Riddle


Played 20234 Times
Description You are given two ropes and a lighter. Both ropes take exactly one hour to burn. Some parts of the ropes are thicker than other parts of the rope, therefore not all parts of the rope will burn at the same speed. Consequently burning half the rope will not necessarily take 30 minutes. Goal: Find a way to Measure 45 minutes of time.

Pirate's Dilemma Riddle


Played 13413 Times
After pillaging another ship, five blood thirsty pirate's arrive on their boat with a chest of 100 gold coins. The pirates have a very unique way of dividing the gold. The pirates all have ranks '1' through '5'. The pirate's allow 'pirate 1' to divide up the gold however he wants. But then the pirates vote whether they are in favor or against the outcome. If they are against the outcome. 'Pirate 1' is thrown overboard. Then 'Pirate 2' is given a chance to divide up the gold. And so forth. -All the pirate have perfect logic and will make the decision to grant themselves the most gold -during the voting if it is a tie the pirate is thrown overboard. -these are bloodthirsty pirate, if it's turns out they'll end up with the same amount of gold they'll chose to kill. You are pirate 1 and must divide up the gold. How much gold must you give each other pirate to stay alive?

Card Proposition Riddle


Played 12999 Times
You are given a betting proposition by an anonymous dealer. The dealer tells you he has a deck of 1000 cards, each card has a random number on it. The number could be any number, negative or positive, the numbers have no limit. The dealer says he'll flip over each card one by and one and you'll have to tell to him when to stop. If you stop and it turns out the card he just flipped is the highest card in the deck he'll give you 5 times your bet. How can you come up with a technique that will lead to a positive outcome?

Weighing Coins Riddle


Played 12743 Times
You are given 27 coins and a balance scale. All the coins weigh the same amount except one coin is counterfeit and weights slightly less. What is the least amount of times that you have to use the scale to ensure you find the counterfeit coin. And how is this possible?

Mysterious Picture Riddle


Played 12532 Times
I am looking at a picture of somebody. It has a caption. The caption reads: "Brothers and sisters have I none, but that man's father is my father's son. Who is that man?"

Missing Dollar Riddle


Played 12688 Times
Three men stroll into a restaurant and share a $30 meal. After paying for the meal, the owner of the restaurant realizes the waiter overcharged the men, and orders the waiter to return $5 back to the men. Not knowing how to divide the money the waiter decides to keep $2 and give each of the men $1 back. So each man ended up paying $9 ($10-$1), the waiter kept $2. So thats $9+$9+$9+$2 = $29. Where did the last dollar end up?

Toggler Riddle


Played 17285 Times
You are in a room with five people. One of them will always tell you the truth. The other four will toggle between telling you the truth, and lying to you. However they can either tell you the truth OR lie on the first question you ask them. After that they must always toggle between that and the opposite. For example. I see one has a mustache, and he is a toggler. I ask - "Do you have a mustache?" "Yes." I ask again. "No." I ask again. "Yes." OR I ask - "Do you have a mustache?" "No." I ask again. "Yes." I ask again. "No." The challenge of the riddle is to ask exactly TWO questions to anyone. You can ask both questions to the same person or ask questions to two different people, and at the end of your two questions you must find out who the truth-teller is.