Logic riddles and mind puzzles for everyone.

# Brain teasers for adults and party puzzles

## Dwarfs

Evil warlock doesn't like dwarfs so he chooses four of them and buries them into the ground so that only their heads are above surface. Dwarfs can't move at all and they can look only forward.

They're buried in a line and one of them is separated by a wall. They are all facing the same direction: last dwarf sees two heads of his friends and a wall. Second last sees only one had and a wall. Second dwarf sees only the wall and first is looking to the distance where he can see nothing interesting though.

Warlock explains the situation to dwarfs and tells them that he has placed hats on their heads - two blue hats and two red ones. One of the dwarfs is supposed to say what color is the hat he is wearing. If he says the right color warlock will dig them out immediately. If he says something else all of them will stay there till the end...

How will dwarfs solve this problem?

## Bulbs

You are standing next to three switches. You know these switches belong to three bulbs in a room behind a closed door – the door is tight closed, and heavy which means that it’s absolutely impossible to see if any bulb is on or not. All three switches are now in position off.

You can do whatever you want with the switches and when you are finished you open the door and go into the room. While in there you have to tell which switch belongs to which bulb.

How will you do that?

## Cake

Can you divide a cake in 8 pieces with three cuts?

## Cannibals

A river. Three cannibals and three missionaries are standing on one bank. There is a boat with maximum capacity of two people. How do they get to the other side so that missionaries are never outnumbered by cannibals on any bank?

## Clown and the King

Once upon a time there was a kingdom. A king and a clown lived in this kingdom. Unfortunately they hated each other so they agreed that they will poison each other one day.

There are only twelve vials of poison in whole kingdom and they are locked in one chamber in the castle.

The poisons have numbers from 1 to 12. The higher the number the stronger the poison. Effect on human body is simple – you drink the poison, you die. Each stronger poison neutralizes all weaker poisons which means that poison 12 neutralizes all poisons, number 11 all poisons but 12 etc. (If you drink 11 and than 12 nothing happens. If you drink 12 and than 11 you die.)

The king enters the chamber with poisons first and takes all the even poisons (2, 4, 6, 8, 10, 12). Than the clown enters and takes the rest. They meet in the throne hall where each fills one cup and hands it over to the other who immediately drinks it. Now each fills the cup once again, now for himself, and drinks it (hoping to save his own life).

What did the clown do that he woke up the second morning and the king was dead?

Premises: Each of them (the king and the clown) PRIMARILY wants to survive. If he survives he wants to poison the other as surely as possible. There is one dose of each poison – it’s not possible to divide it. The poisons are fluids without color or smell and they have the same consistency as water.

## Cogwheels

You have an appliance like this:

There are two cogwheels in a box. The bigger one has 24 teeth and it is tightly attached to the center of the box (it doesn’t turn or move). The smaller one has 8 teeth and it rotates around the bigger wheel. How many times does the smaller wheel turn compared with the box when it turns once around the bigger wheel?

## Condoms

Two men and women have shipwrecked on a deserted island. They are bored so they want to want to have some fun (sex). As there is a plenty of time each one of them wants to try all possible (heterosexual) partners.

The problem is that each of them has a different STD and if anyone was to catch another one he/she would hardly survive. They have two condoms that the men had brought. How are they supposed to plan they’re sexual activities so that every woman would have sex with every man and they would prevent spreading STD’s at the same time?

(Condoms are ideal, they last a lot but the used side can’t get to contact with the particular part of a different body)

## Cross

Can you cut and reassemble a square so that you create a red cross of the same volume?

(A cross is made of 5 identical squares)

## Dad

Mom is 21 years older than her son.

In 6 years she will be 5 times older than her son.

Where is the father right now?

## Death match

You have just arrived to Wild West and you have already got in trouble. Buffalo Bill and Killer Kid are aiming at each other with colts. They accept you to death match with pleasure. They don’t want to waste bullets so they agree on following rules:

- Participants shoot in given order until only one survives.
- Everyone shoots only once when it’s his turn.
- If someone is injured the others finish him off with iron rod.
- The worst shooter (you) shoots first the best shoots last.

What tactics will you choose if you know that you hit about every third shot, Bill has around 50% chance and Immortal Kid never miss? (Please don’t shoot yourself)

## Fire

Group of friends is trapped in a burning house. The house is going to collapse in 12 minutes so they desperately want to get out. They have to run through a hallway which is in flames. If someone wants to pass through he has to have a fire extinguisher to hold the flames back at least a little. Problem is that the friends have only one.

Only two people can go at once. Than somebody has to return with the extinguisher and other two can go.

There is one fireman among the friends who moves through flames with ease and he can ran through the hallway in one minute. His best friend who is in great shape can run through in 2 minutes. There is an older man who needs four minutes and a drunken guy who will need 5 minutes to pass through. If two people go together they move at speed of the slower one.

How will they do it so that they all get out before the house collapses?

## Grain

Poor farmer went to the farmers market to sell his corn. He had only one sack so he put barley into one half of the sack tied it in the middle and filled the other half with wheat.

He found a buyer at the market who unfortunately wanted only barley which was at the bottom. The buyer had also only one sack and he didn’t want to switch sacks as his one was bigger.

How did they get the barley from one sack to the other without pouring the grain somewhere else?

## Heads – tails

As it often happens in life evil warlock imprisoned a wise man. Surprisingly he gave him a chance to save himself if he fulfils one task.

There is a round tray on the table which can be turned around freely. There are four coins on the tray placed as corners of a square.

Wiseman has his eyes covered so he doesn’t see anything. His task is to turn the coins so that they are all heads up.

He is not in easy situation. He may turn some coins and than the warlock will turn the tray around. He turns some coins again warlock turns the tray again. It goes on until all coins are turned correctly. At that moment evil warlock ends the game.

Wiseman can’t recognize one side from the other by touching it. He has to leave the coins where they were in the corners of a square. And mainly – because of the evil magic – he has the worst luck so if he relies just on chance he will never fulfill the task.

## Jigsaw

Both triangles are made of identical parts. In the bottom one is one empty square though. How is that possible?

## Lords

Three lords enter a hotel. The receptionist at the front desk tells them that one room is 10 pounds so each of the gentlemen pay – 30 pounds altogether.

When the porter wants to bring the luggage to lord’s rooms, hotel director rushes in to tell him that it was supposed to be only 25 pounds for the three rooms and he gives him the extra 5 pounds to return them to lords.

The porter had no idea know how to divide 5 pounds between 3 gentlemen so he gave one pound to each of them and kept the remaining 2.

Each lord paid 9 pounds (10 originally and got one back). 3x9=27. The porter kept two pounds. 27+2=29. What happened with the remaining one pound?

Imagine you want to send a valuable item to your friend. You have big enough box on which you can place several padlocks. You both have enough padlocks but the problem is that you don’t have keys to padlocks of the other one.

How do you send the valuable item so that it doesn’t go unlocked? Sending just a key doesn’t help because someone could replicate it.

## Money bags

You have 10 bags of gold coins (you wish :)).

One of your servants who were responsible for transport of the money wanted to trick you. He took one of the money bags and filed away one gram of gold from each coin. One coin normally weighs 10 grams.

Can you figure out in one scaling which bag contains lighter coins – which servant should be fired – using digital scales (shows the exact weight of an item)?

## Mother-in-law

Man comes home and what does he see? Mother-in-law came over.

I don’t know how but they started a fight. About what is not important at all.

...

Mother-in-law: You just lie all the time.

Man: No way...

Mother-in-law: You don’t tell a sentence without lying!

Man: Don’t be ridiculous!

Mother-in-law: Let’s try it: tell me one true sentence.

Man: Ok but you will get out after.

Mother-in-law: If you tell me true sentence I’ll go but if you will lie again I will stay. I promise I will!

Man thought for a while and than told her one sentence. Mother-in-law suddenly realized that to keep her promise she has to hang herself.

What did the man tell her?

## Nine Coins

You were given nine same looking coins of which one is fake – weighs less. You can use even arm balance. How do you find out which coin is fake in two scalings?

## Pirates

Five pirates stole a treasure – exactly hundred gold coins.

Pirates have a special way of dividing their loot:

- The oldest one suggests how he would split up the loot.
- Everyone votes.
- If he gets more than half votes they split the loot according to his proposal.
- If he doesn’t the others kill him and the process starts all over again – without the dead pirate.

All pirates are very used to this way of dividing and they never break the rules. Everyone’s top priority is his life. Second is money. And if there is no money or life involved in his decision he likes to harm the others.

How will they split the loot?

## Points

There are nine points as shown in the picture above. Can you connect them with four straight lines without lifting pen from a paper?

(It might look like circles in the pictures but its points)

## Ropes

You have two ropes. Each of them burns for one hour. They burn unevenly in different parts though – it means that one half can burn for 20 minutes and other half for 40 minutes. In addition you have a box of matches.

Measure 15 minutes!

## Sheep

If we tie a sheep to one peg it eats out a circle in grass. If we put a rope through a ring on its neck and tie both ends of the rope to two pegs it eats out an ellipse. If we want an oval we tighten one rope between two pegs put a ring with a rope on it and tie the sheep to its other end.

How to tie a sheep so that it eats out a square in grass? We have one sheep ropes pegs and rings.

## Steaks

It takes 10 minutes to fry one steak - 5 minutes from each side. Two steaks can fit on a pan. What is the shortest possible time to fry 3 steaks?

## Three Chinamen

There are three Chinese guys sleeping in a hotel room. Someone paints their faces with black color during the night. When they wake up in the morning they look at each other and all start laughing.

If one of them realizes he is black too he stops laughing. Because they are all smart and they know it about each other one of them will realize it soon. How did he find out?

Just realize that if two friends are dirty it means that I am too. If I see two laughing dirty guys it doesn’t mean that I’m dirty too they might be laughing at each other and I might be clean. Chinese didn’t point or say anything.

## Trail

You are sentenced at court.

Judge is a fair guy so he offers you following:

“You can say one sentence to defend yourself. If you lie we will hang you. If you tell us the truth we will shoot you.”

What will you say?

## Two pitchers

You have two pitchers 5-liter and 3-liter (liter is approx. 2 pints) and unlimited supply of water. Can you measure out 4 liters?

## Where is the car?

There are three doors in front of you. New car waits behind one of them; goat is hidden behind each of the remaining two. You may open one of the doors and get what is behind them. You want the car off course. You choose your door. Moderator (who knows where the car is) than opens one of the remaining doors and shows that there is goat. Now he gives you the opportunity to change your decision.

You are standing in front of two closed doors. Will you change your decision?