With a partner ask questions about the following problems so that you can work towards a solution:
1. You are driving down the road in your car on a wild, stormy night, when you pass by a bus stop and you see three people waiting for the bus
Knowing that there can only be one passenger in your car, whom would you choose?
2. Acting on an anonymous phone call, the police raid a house to arrest a suspected murderer. They don't know what he looks like but they know his name is John and that he is inside the house. The police bust in on a carpenter, a lorry driver, a mechanic and a fireman all playing poker. Without hesitation or communication of any kind, they immediately arrest the fireman. How do they know they've got their man?
3. A man lives in the penthouse of an apartment building. Every morning he takes the elevator down to the lobby and leaves the building. Upon his return, however, he can only travel halfway up in the lift and has to walk the rest of the way - unless it's raining. What is the explanation for this?
4. How could a baby fall out of a twenty-story building onto the ground and live?
5. A little girl was warned by her guardian never to open the cellar door or she would see things that she was not meant to see. One day while her guardian was out she did open the cellar door. What did she see?
6. A man and his son are in a car crash. The father is killed and the child is taken to hospital gravely injured. When he gets there, the surgeon says, 'I can't operate on this boy - for he is my son!!!' How can this possibly be?
7. There are six eggs in the basket. Six people each take one of the eggs. How can it be that one egg is left in the basket?
8. A daughter of a wealthy merchant had fallen in love with a young man and they wished to marry. Her father, however, wanted her to marry a friend of his, another wealthy merchant, a man who was old and ugly and whom the daughter did not love. On approaching him about her love for the young man the father said that he would allow his daughter to marry the man of her choice if she could pull a white stone from a bag containing one black and one white stone. He bent down to pick up the stones from the path where they stood and put them into a bag. His daughter noticed that he had placed two black stones in the bag so she could not draw a white one and choose her own husband. How did she resolve this problem and choose the man she loved?
Four Tasmanian camels travelling on a very narrow ledge encounter four Tasmanian camels coming the other way.
Tasmanian camels never go backwards, especially when on a precarious ledge. The camels will climb over each other, but only if there is a camel sized space on the other side.
The camels didn't see each other until there was only exactly one camel's width between the two groups.
How can all camels pass, allowing both groups to go on their way, without any camel reversing?
Three men in a cafe order a meal the total cost of which is $15. They each contribute $5. The waiter takes the money to the chef who recognizes the three as friends and asks the waiter to return $5 to the men.
The waiter is not only poor at mathematics but dishonest and instead of going to the trouble of splitting the $5 between the three he simply gives them $1 each and pockets the remaining $2 for himself.
Now, each of the men effectively paid $4, the total paid is therefore $12. Add the $2 in the waiters pocket and this comes to $14.....where has the other $1 gone from the original $15?
There are three boxes. One is labeled "APPLES" another is labeled "ORANGES". The last one is labeled "APPLES AND ORANGES". You know that each is labeled incorrectly. You may ask me to pick one fruit from one box which you choose.
How can you label the boxes correctly?
Three cannibals and three anthropologists have to cross a river.
The boat they have is only big enough for two people. The cannibals will do as requested, even if they are on the other side of the river, with one exception. If at any point in time there are more cannibals on one side of the river than anthropologists, the cannibals will eat them.
What plan can the anthropologists use for crossing the river so they don't get eaten?
Note: One anthropologist can not control two cannibals on land, nor can one anthropologist on land control two cannibals on the boat if they are all on the same side of the river. This means an anthropologist will not survive being rowed across the river by a cannibal if there is one cannibal on the other side.
A mother is 21 years older than her child. In exactly 6 years from now, the mother will be exactly 5 times as old as the child.
Where's the father?
You are trapped in a room with two doors. One leads to certain death and the other leads to freedom. You don't know which is which.
There are two robots guarding the doors. They will let you choose one door but upon doing so you must go through it.
You can, however, ask one robot one question. The problem is one robot always tells the truth ,the other always lies and you don't know which is which.
What is the question you ask?
A frog is at the bottom of a 30 meter well. Each day he summons enough energy for one 3 meter leap up the well. Exhausted, he then hangs there for the rest of the day. At night, while he is asleep, he slips 2 meters backwards. How many days does it take him to escape from the well?
Note: Assume after the first leap that his hind legs are exactly three meters up the well. His hind legs must clear the well for him to escape.
You can paddle your canoe seven miles per hour through any placid lake. The stream flows at three miles per hour. The moment you start to paddle up stream a fisherman loses one of his bobbers in the water fourteen miles up stream of you.
How many hours does it take for you and the bobber to meet?
Cathy has six pairs of black socks and six pairs of white socks in her drawer.
In complete darkness, and without looking, how many socks must she take from the drawer in order to be sure to get a pair that match?
You have a chessboard with two opposite squares cut out. How can you cover the remaining 62 squares completely with 31 domino pieces ?(without breaking the dominoes or the board of course). Each domino covers exactly two squares.
Three co-workers would like to know their average salary. how can they do it, without disclosing their own salaries?
The name of the game is Petals Around the Rose, and that name is significant. Newcomers to the game can be told that much. They can also be told that every answer is zero or an even number. They can also be told the answer for every throw of the dice that are used in the game. And that's all the information they get.
The person who has the dice and knows the game, rolls five dice and remarks almost instantly on the answer. For example: in Roll #1 the answer is two.
Roll #1.
"The answer is what?" says the new player.
"Two."
"On that roll?"
"Yes."
"Would it still be two if I moved the dice without turning any of them over, just rearranging the pattern?"
"I can tell you only three things: the name of the game, the fact that the answer is always even, and the answer for any particular throw. In this case the answer is two."
"So that's how it is. What am I supposed to do?"
"You're supposed to tell me the answer before I tell you. I'll give you all the time you want, but don't tell me your theory, just the answer. If you figure it out, you don't want to give the idea away to these other jokers around you. Make them work for the answers, too. If you get the answer right on six successive rolls, I'll take that as prima facie evidence that you understand the game."
"OK, roll again."
Roll #2.
"I give up. What's the answer?"
"The answer is eight."
"Roll again."
Roll #3.
The answer is fourteen.
Roll #4.
The answer is zero.
Roll #5.
The answer is four.
Roll #6.
An integral part of the puzzle is that those who have solved it are urged to keep the solution a secret, so there is no solution posted here. It is not a hard puzzle to figure out however.
A claim that often accompanies these instructions is that the smarter an individual, the greater amount of difficulty the individual will have in solving it. If such a statement is true, it may be attributed to the fact that "smarter" people tend to be more knowledgeable in a wide range of information which they may unnecessarily attempt to draw upon to solve the puzzle.
With Music! (Turn the sound off!)
When you know the secret think of some alternative rules.
The Petals problem provides an example of problem solving where you work from hunches and look for patterns that would link the data to the answers. Which of the techniques in the Wikipedia article fits this approach to problem solving? Which approaches match your attempts to solve the previous problems?
The Petals problem provides an example of inductive reasoning: examine examples and seek out general rules from the empirical evidence. Some would argue that inductive reasoniong is logically unsound as it is impossible to examine all of the potentially infinite number of examples. In the case of a computer program, which is a sequence of instructions in a machine (an algorithm) it would seem to be quite sound. Once you have discovered the pattern in the puzzle all the programmed outcomes should fit the algorithm. If any case arises that does not fit the pattern then an error must have occurred in the computer's hardware or software.