Logical Puzzles

  1. A farmer needs to take a fox, a rabbit and a carrot across a river (No, I don't know why either). He owns a boat which is so small that there is only enough room for him and one other item. The problem is that he can't leave the fox with the rabbit, because the fox will eat the rabbit, and he can't leave the rabbit with the carrot, because the rabbit will eat the carrot. The good news is that neither the fox nor the rabbit will wander off if he leaves them on the bank.

    Use the diagram below to pretend that you're the farmer. Click on any of the three items to load/unload the boat, and the boat itself to cross the river. Can you get the three items from the left bank to the right bank without anything being eaten?

  2. You have two water jugs, one of which holds 3 litres and the other of which holds 5 litres, and an unlimited supply of water from a water tap. You also have a drain, down which you can pour water. By transferring water between the two jugs, you need to get exactly 4 litre in the larger jug (so you can't just look in the jug and guess it's about right). Assume that no water is lost when you pour from one jug to the other.
    Click on one of the following buttons:

    5 litre jug 3 litre jug
    0 litres 0 litres

    It might interest you to know that this puzzle appeared in the film Die Hard 3. The two main characters in the film had to weigh out 4 litres of water in the 5 litre jug, and if the weight was wrong by so much as an ounce, a huge bomb would go off! (They succeeded)

  3. The Ruritanian language has no words for "the" or "a". Those words are just missed out. Here are some sentences in Ruritanian, together with their English translations:
    Gloo snob blick=The cat drinks milk.
    Pnar fning glop=The dog eats meat.
    Zbip dar blick=The man drinks beer.
    Gloo pnar ting=The cat hates the dog.
    Zbip fning dill=The man sees meat.

    How would you translate the following sentences into Ruritanian?

    The dog hates milk.
    The cat sees beer.
    The man eats the dog.
    The cat hates meat.

  4. Professor Plum's car has started making some funny noises. When he moves the gear stick, closes the door and turns on the ignition, there is a buzz and a rattle. When he closes the door, turns on the headlights and opens the sunroof, there is a rattle and a clunk. When he opens the sunroof, turns on the ignition and operates the windscreen wipers, there is a clunk, a buzz and a thud.

    Which action causes which noise?
    Moving the gear-stick a rattle a clunk a buzz a thud no noise at all.
    Closing the door a rattle a clunk a buzz a thud no noise at all.
    Turning on the headlights a rattle a clunk a buzz a thud no noise at all.
    Opening the sunroof a rattle a clunk a buzz a thud no noise at all.
    Turning on the ignition a rattle a clunk a buzz a thud no noise at all.
    Operating the windscreen wipers a rattle a clunk a buzz a thud no noise at all.

  5. You have a weighing scales like the ones you see here, that let you weigh one object against another, and three cricket balls. All the balls are identical apart from the fact that one weighs a little more than the other two. You can't tell which is heavier just by holding them, but you are allowed to use the scales only once. How could you tell which ball was heavier with only one weighing?

    Now you are given 9 cricket balls, all identical except for one which is heavier than the other 8. This time you are allowed to use the scales twice. How could you identify the heavier ball?

  6. Jack is looking at Anne. Anne is looking at George. Jack is married, George is not, and we don't know if Anne is married. Is a married person looking at an unmarried person?

    Yes No

  7. The day before two days after the day before tomorrow is Saturday. What day is it today?

  8. On a certain island, there are three tribes of people. The Pukkas always tell the truth. The Wotta Woppas never tell the truth. The Shilli Shallas make statements that are alternatively true, then false, then true, then false etc. (or false, then true, then false, then true etc.)

    You meet three individuals, A, B and C, one from each tribe, but you don't know which person is from which tribe. They make statements as follows:

    B is a Wotta Woppa.


    C is a Shilli Shalla.


    I am a Wotta Woppa.


    Person A is a Pukka Wotta Woppa Shilli Shalla.
    Person B is a Pukka Wotta Woppa Shilli Shalla.
    Person C is a Pukka Wotta Woppa Shilli Shalla.

  9. The day before yesterday, I was only 25 but my 28th birthday is next year. How is that possible?

  10. What is the number of the parking space in which the car is parked?


  11. It's said that Einstein created this logic puzzle in the 19th century, and it's often claimed that 98% of the world population could not solve it.

    There are five houses next to each other. Each one is painted a different color. Each house owner is from a different country, drinks different beverages, smokes different brands of cigarettes and has different pets. It is up to you to answer two questions: Who owns the snake? Who drinks water?

    House 1 House 2 House 3 House 4 House 5
    • The Englishman lives in the red house.
    • The Swede owns a dog.
    • The Dane drinks tea.
    • The green house is directly to the left of the white house.
    • The owner of the green house drinks coffee.
    • The man who smokes Kools owns a bird.
    • The owner of the yellow house smokes Dunhill.
    • The owner of the middle house drinks milk.
    • The Norwegian lives in the first house.
    • The man who smokes Blends lives next to the cat owner.
    • The horse's owner lives next to the man who smokes Dunhill.
    • The man who smokes Masters drinks beer.
    • The German smokes Prince.
    • The Norwegian lives next to the blue house.
    • The man who smokes Blends has a next-door neighbour who drinks water.
    What is the house number of the person who owns the snake?
    What is the house number of the person who drinks water?