A student has missed an excessive number of days at school and thus the principal called him to his office and requested for an explanation. The student said, “There just isn’t enough time for school. I need 8 hours of sleep a day, which adds up to about 122 days a year. Weekends off is 104 days a year. Summer vacation is about 60 days. If I spend about an hour on each meal, that’s 3 hours a day or 45 days a year. I need at least 2 hours of exercise and relaxation time each day to stay physically and mentally fit, adding another 30 days. Add all of that up and you get about 361 days. That only leaves 4 days for school.” The principal is confused, but can’t figure out why. What is wrong with the student’s argument?

There is a row of soldiers that is 1km in length and they walk with a constant speed in a straight line, in one direction. All the way at the end walks a messenger. He has to bring a message to the captain walking all the way at the beginning of the row. The messenger starts walking past the soldiers and immediately turns around when arriving at the captain and walks back to the end of the row. When the messenger is back at the end, the whole group of soldiers have traveled a distance of 1 km. The soldiers and captain are walking at the same constant speed. The messenger (walking faster then the soldiers) is also walking a a constant speed. You don’t know anything about time or speed. How far did the messenger travel from the end of the row to the beginning and back?

A crime has been committed at Freemont Street. The main suspect is a man named Sean Baker. It was said that a man had been walking along the pathway when he was suddenly shot in the stomach. The suspect had brown hair, blue eyes and wore a baggy Armani suit just like Sean Baker’s. Sean was asked to tell the story right from the beginning. “Well,” said Sean, “I was just hanging around the park when I saw this man walking along the pathway. Suddenly, a guy came up from behind him and shot him! I ran home as fast as I could.” The policemen asked him to give a description of the murderer. “He had a red moustache, red hair and a baggy Armani suit on.” “I think this man is telling a lie,” said one of the policemen. How did he know?

The court takes decision to relax the sentence given to criminal if he can solve a puzzle. Criminal has to take decision to open one of the doors. Behind each door is either a lady or a tiger. They may be both tigers, both ladies or one of each. If the criminal opens a door to find a lady he will marry her and if he opens a door to find a tiger he will be eaten alive. Of course, the criminal would prefer to be married than eaten alive. Each of the doors has a statement written on it. The statement on door one says, “In this room there is a lady, and in the other room there is a tiger.” The statement on door two says,”In one of these rooms there is a lady, and in one of these rooms there is a tiger.” The criminal is informed that one of the statements is true and one is false. Which door should the criminal open?

Once upon a time, in the West Lake village, a servant lived with his master. After service of about 30 years, his master became ill and was going to die. One day, the master called his servant and asked him for a wish. It could be any wish but just one. The master gave him one day to think about it. The servant became very happy and went to his mother for discussion about the wish. His mother was blind and she asked her son for making a wish for her eye-sight to come back. Then the servant went to his wife. She became very excited and asked for a son as they were childless for many years. After that, the servant went to his father who wanted to be rich and so he asked his son to wish for a lot of money. The next day he went to his master and made one wish through which all the three (mother, father, wife) got what they wanted. What was the servant’s wish?

On a certain island there are people with assorted eye colors. There are 100 people with blue eyes and 100 people with brown eyes. Since there are no mirrors on this island, no person knows the color of their own eyes. The people on the island are not allowed to talk or communicate with each other in any way. They are also not aware of the number of blue or brown eyed people on the island. For all they know, they could have red eyes too. But they are allowed to observe other people and keep count of the number of people with a certain eye color. There is a rule that the people on the island have to follow – any person who is sure of their eye color has to leave the island immediately. One day, a person comes to the island and announces to the people that he sees someone with blue eyes. Everyone knows that the person only speaks the truth. What do you think happens?

There is a prison with 100 prisoners, each in separate cells with no form of contact. There is an area in the prison with a single light bulb in it. Each day, the warden picks one of the prisoners at random, even if they have been picked before, and takes them out to the lobby. The prisoner will have the choice to flip the switch if they want. The light bulb starts off. When a prisoner is taken into the area with the light bulb, he can also say “Every prisoner has been brought to the light bulb.” If this is true all prisoners will go free. However, if a prisoner chooses to say this and it’s wrong, all the prisoners will be executed. So a prisoner should only say this if he knows it is true for sure. Before the first day of this process begins, all the prisoners are allowed to get together to discuss a strategy to eventually save themselves. What strategy could they use to ensure they will go free?

A Japanese ship was en route in the open sea. The Japanese captain went for a shower removing his diamond ring and Rolex watch on the table. When he returned, his valuables were missing. The captain immediately called the five suspected crew members and asked each one where and what he was doing for the last 15 minutes. The Filipino cook in a heavy overcoat said, “I was in fridge room getting meat for cooking.” The Indian Engineer with a torch in hand said, “I was working on generator engine.” The Sri Lankan seaman said, “I was on the mast (top of the ship) correcting the flag which was upside down by mistake.” The British radio officer said, “I was messaging to company that we are reaching the next port in 72 hours. From now that is Wednesday morning at 10 AM. The British navigation officer said, “I am on night watch, so sleeping in my cabin.” The captain caught the liar. So who is the thief?

A friend of mine emptied a box of matches on the table and divided them into three heaps, while we stood around him wondering what he was going to do next. He looked up and said, “Well friends, we have here three uneven heaps. Of course you know that a match box contains altogether 48 matches. This I don’t have to tell you. And I am not going to tell you how many there are in each heap.” “What do you want us to do?” one of the men shouted. “Look well, and think. If I take off as many matches from the first heap as there are in the second and add them to the second, and then take as many from the second as there are in the third and add them to the third, and lastly if I take as many from the third as there are in the first and add them to the first—then the heaps will all have equal number of matches.” As we all stood there puzzled he asked, “Can you tell me how many were there originally in each heap?” Can you?

A guard is stationed at the entrance of a bridge. He is tasked to shoot anyone who tries to cross to the other side of the bridge, and to turn away anyone who comes in from the opposite side of the bridge. You are on his side of the bridge and want to escape to the other side. Because the bridge is old and rickety, anyone who tries to cross it does so at a constant speed, and it always takes exactly 10 minutes to cross. The guard comes out of his post every 6 minutes and looks down the bridge for any people trying to leave, and at all other times he sits in his post and snoozes. You know you can sneak past him when he’s sleeping, but the problem is that you won’t be able to make it all the way to the other side of the bridge before he sees you (since he comes out every 6 minutes, but it takes 10 minutes to cross). One day a brilliant idea comes to you, and soon you’ve successfully crossed to the other side of the bridge without being shot. How did you do it?

The King calls in three wise men and tells them to all close their eyes. While their eyes are closed, he goes around and puts a hat on each of them. “I put a blue or white hat on each of you,” the King says. “I won’t tell you what color each hat is, but I promise you that at least one of you has a blue hat.” “Now open your eyes,” he continues. “You may not communicate with each other at all. Within one hour, one of you must call out the color of your own hat. If you aren’t able to do this, or if anyone calls out the wrong color, I will have you all exiled from the kingdom.” The wise men open their eyes and look at the other mens’ hats. They stand there for almost the whole hour in silence, thinking. Just as time is about to run out, all three men figure out the color of their own hats and yell the colors out at the same time. You can assume that all three men are perfect logicians, that they know that the others are perfect logicians, and that they all think at the same speed. What colors are the three men’s hats?

Five potential donors are sitting on a bench from left to right outside the surgery room and are waiting for the doctor. Their ages are 6, 10, 31, 47 and 61. Their heights are 41, 49, 61, 66 and 75 inches. Their weights are 41, 76, 97, 126 and 166 pounds. Determine the position, blood group, age, height and weight of each of them with the help of the following ten hints. The person on the far right is 37 years older than Jimmy, and is 61 inches tall. Jimmy weighs 56 pounds more than his height. Alexandrio weighs 76 pounds and is 75 inches tall. Justin is type AB and weighs 56 pounds less than Jimmy. The person in the center is 10 years old, is blood type AO and weighs 97 pounds. Andrew, who is the first, is 66 inches tall, and weighs 100 pounds more than his height. The person who is blood type O, is 25 years older than the person to the left of them. Kian is 61 years old. The person who is blood type A, is 55 years younger than Kian and is not next to the person who is type AO. The person who is next to the 10 year old but not next to the person who is 66 inches tall, is blood type B, and weighs 126 pounds.

Three Gods A, B, and C are called, in no particular order, True, False, and Random. True always speaks truly, False always speaks falsely, but whether Random speaks truly or falsely is a completely random matter. Your task is to determine the identities of A, B, and C by asking three yes-no questions; each question must be put to exactly one God. The Gods understand English, but will answer all questions in their own language, in which the words for yes and no are “da” and “ja”, in some order. You do not know which word means which. It could be that some God gets asked more than one question (and hence that some God is not asked any question at all). What the second question is, and to which God it is put, may depend on the answer to the first question. (And of course similarly for the third question.) Whether Random speaks truly or not should be thought of as depending on the flip of a coin hidden in his brain: if the coin comes down heads, he speaks truly; if tails, falsely. Random will answer “da” or “ja” when asked any yes-no question. What would your three questions be?

A king has 100 identical servants, each with a different rank between 1 and 100. At the end of each day, each servant comes into the king’s quarters, one-by-one, in a random order, and announces his rank to let the king know that he is done working for the day. For example, servant 14 comes in and says, “Servant 14, reporting in.” One day, the king’s aide comes in and tells the king that one of the servants is missing, though he isn’t sure which one. Before the other servants begin reporting in for the night, the king asks for a piece of paper to write on to help him figure out which servant is missing. Unfortunately, all that’s available is a very small piece that can only hold one number at a time. The king is free to erase what he writes and write something new as many times as he likes, but he can only have one number written down at a time. The king’s memory is bad and he won’t be able to remember all the exact numbers as the servants report in, so he must use the paper to help him. How can he use the paper such that once the final servant has reported in, he’ll know exactly which servant is missing?

One day, a father went to his three sons and told them that he would die soon and he needed to decide which one of them to give his property to. He decided to give them all a test. He said, “Go to the market my sons, and purchase something that is large enough to fill my bedroom, but small enough to fit in your pocket. From this I will decide which of you is the wisest and worthy enough to inherit my land.” So they all went to the market and bought something that they thought would fill the room, yet was still small enough that they could fit into their pockets. Each son came back with a different item. The father told his sons to come into his bedroom one at a time and try to fill up his bedroom with whatever they had purchased. The first son came in and put some pieces of cloth that he had bought and laid them end to end across the room, but it barely covered any of the floor. Then the second son came in and laid some hay, that he had purchased, on the floor but there was only enough to cover half of the floor. The third son came in and showed his father what he had purchased and how it could fill the entire room yet still fit into his pocket.The father replied, “You are truly the wisest of all and you shall receive my property.” What was it that the son had showed to his father?