Carefully selected logic riddles and mind puzzles. Test your brain.
Logic 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?
Bus
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?
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)
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?
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.
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?
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?
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?
