Hard Brain Teasers

Balls In A Box - Hard


Four blindfolded girls were each given an identical box, containing different colored balls. One contained 3 black balls; one contained 2 black balls and 1 white ball; one contained 1 black ball and 2 white balls; and the fourth contained 3 white balls. Each box had a label on it reading "Three Black" or "Two Black, One White" or "One Black, Two White" or "Three White." The girls were told that none of the four labels correctly described the contents of the box to which it was attached. Each girl was told, in turn, to draw 2 balls from her box, at which point her blindfold was removed so that she could see the 2 balls in her hand and the label on the box assigned to her. She was given the task of trying to guess the color of the ball remaining in her box. As each girl drew balls from her box, their colors were announced for all the girls to hear; but the girls cold not see the labels on any other box other than their own. The first girl, having drawn 2 black balls, announced: "I know the color of the third ball." The second girl drew 1 white and 1 black ball, and similarly stated: "I know the color of the third ball." The third girl withdrew 2 white balls, looked at her label, and said: "I can't tell the color of the third ball." Finally, the fourth girl declared: " I don't need to remove my blindfold or any balls from my box, and yet I know the color of all three. What's more, I know the color of the third ball in each of your boxes as well." The first three girls were amazed by the fourth girl's assertion and promptly challenged her. She proceeded to indentify the contents of each box correctly. How?

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Census Taker - Hard


A census taker approaches a house and asks the woman who answers the door,"How many children do you have, and what are their ages?" Woman: "I have three children, the product of their ages are 36, the sum of their ages are equal to the address of the house next door." The census taker walks next door, comes back and says, "I need more information." The woman replies, "I have to go, my oldest child is sleeping upstairs." Census taker: "Thank you, I have everything I need." Question: What are the ages of each of the three children?

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Einstein's Brain Teaser - Hard


There are 5 houses in different colors. In each house lives a person with a different nationality. The 5 owners drink a certain type of beverage, smoke a certain brand of cigar, and keep a certain pet. No owners have the same pet, smoke the same brand of cigar, or drink the same beverage.

The question is "Who owns the fish?"

  • The Brit lives in the red house.
  • The Swede keeps dogs as pets.
  • The Dane drinks tea.
  • The green house is on the left of the white house.
  • The green house's owner drinks coffee.
  • The person who smokes Pall Mall rears birds.
  • The owner of the yellow house smokes Dunhill.
  • The man living in the center house drinks milk.
  • The Norwegian lives in the first house.
  • The man who smokes Blends lives next to the one who keeps cats.
  • The man who keeps the horse lives next to the man who smokes Dunhill.
  • The owner who smokes Bluemasters drinks beer.
  • The German smokes Prince.
  • The Norwegian lives next to the blue house.
  • The man who smokes Blends has a neighbor who drinks water.

    ** Einstein wrote this riddle. He said 98% of the world could not solve it. **

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    Patterns 1 - Hard

    In which direction should the missing arrow point ?


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    Check's in the Mail - Hard


    A man received a check. The pounds had been transposed for pence and vice versa. He went out, spent 5 pounds and 42 pence but discovered that he now had exactly six times the value of the correct check. What amount should he have received?

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    Corresponding Letters - Hard


    What letter should be placed in the fourth grouping ?

    AME  =   P
    RUB  =  R
    SAP  =   B
    EME  =  ?

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    Missing Number - Hard

    6 7 4 3 7
    2 5 4 9 1
    7 6 5 2 8
    4 3 6 7 3
    5 8 3 4 ?


    What number is missing?

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    Safe Harbour - Hard


    A ship is battling against the tide to safety. It uses 9.5 gallons of fuel every hour and sails at 23 mph. It is 34 miles from safety but the flow against it is 12 mph. It has 30 gallons of fuel left. Will it reach safety ?

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    Fresh Fruit - Hard


    One satsuma, one apple and two pears cost 51 cents . Two pears and two satsumas cost 42 cents and one apple, one pear and two satsumas cost 44 cents. How much will two apples and two satsumas cost ?

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    Busy Travel Agent - Hard


    During a week a travel agent has taken 32 bookings for Tenerife, 30 for Majorca and 18 for Ibiza. How many bookings has it taken for Portugal ?

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    Distances - Hard


    Distances from you to certain cities are written below.

    BERLIN 200 miles
    PARIS 300 miles
    ROME 400 miles
    AMSTERDAM 300 miles
    CARDIFF ??? miles

    How far should it be to Cardiff ?

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    Coin in a Bottle - Hard


    If you put a coin in an empty bottle and insert a cork into the neck of the bottle, how could you remove the coin without taking the cork out or breaking the bottle?

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    Surgery in the Woods - Hard


    Three surgeons and a clumsy cook go camping in the remote wilderness. The clumsy cook stumbles over the campfire as he is serving the surgeons, injuring himself and dumping hot stew on the hands of the surgeons. The cook's injuries need surgical treatment. The surgeons' injuries are minor but open. It turns out they brought the equipment necessary for the cook's surgery with them, and they can use the campfire to sterilize the tools. But there are only two rubber gloves. Because of the different surgeons' skills, all three of the surgeons are needed to operate on the cook, in sequence. How can this be done without any of them being exposed to the blood of any of the others?

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    Rope Thief - Hard


    Two fifty foot ropes are suspended from a forty foot ceiling twenty feet apart. You have only a knife. How much of the rope can you steal?

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    Wrestling Team - Hard


    On the varsity wrestling team there are 8 wrestlers. The coach is trying to seperate the wrestlers by weight class for their first competition. The wrestlers names are Jeff, Bill, Carl, David, Ryan, Frank, George, and Trevor are basketball players.

    Frank is in the same weight class as Trevor.
    George is in a heavier weight class than than Frank.
    Ryan is in a heavier weight class than than Jeff.
    Jeff is in a heavier weight class than than David and Carl.
    Bill is in a lighter weight class than Carl.

    Which one of the following must be false?

    (A) George is in a heavier weight class than than Trevor.
    (B) Carl is in a heavier weight class than than David.
    (C) Jeff is in a heavier weight class than than Frank.
    (D) David is in the same weight class as Carl.
    (E) Bill is in the same weight class as Ryan.

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