Brainteasers · Fun Logic

It’s not that I’m so smart, it’s just that I stay with problems longer.
Albert Einstein

It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth.
Sherlock Holmes

You know my method. It is founded upon the observation of trifles.
Sherlock Holmes

Inspector Martin: By George! How ever did you see that?
Sherlock Holmes: Because I looked for it.

There are 12 balls of equal size and shape, but one is either lighter or heavier than the other 11. Using no more than 3 balances, determine which ball is lighter or heavier.

You are standing at a fork in the road. One branch leads to T-town where everyone always tells the truth, and the other branch leads to F-town where everyone always tells lies. The sign at the fork has obviously been spun around many times, and someone is adjusting the sign yet again, but you don’t know which town the person lives in. What single question can you ask to determine with absolute certainty which road leads to T-town?

You finally arrive in T-town and discover it’s market day and residents of both towns are present. You hear the following comments:

• Eeny: Meeny is a liar
• Meeny: Eeny and Miney are liars
• Miney: Moe is a liar
• Moe: Only Meeny tells the truth

Who is from T-town and who is from F-town?

A T-town detective asks you to help identify a thief who is known to work alone. Before their capture, three suspects swapped identity cards after obscuring their photos and physical descriptions. The ID cards do reveal that 1 suspect is from T-town and the other 2 from F-town. The suspects make these statements:

#1: I’m innocent.
#2: I’m innocent.
#3: #2 did it.

Who’s guilty?

5 people with different jobs live in houses of different colors. No one drives the same make vehicle, does the same workout or drinks the same beverage. Check off the 15 clues below as you use them.

What’s the temperature when it’s twice as cold as 0 degrees?

Each of three switches controls a light in another room. You cannot see the lights when you are able to see or touch the switches. You may only check the lights once. Determine which switch controls which light.

Two fathers and two sons have a total of $30 between them. Each man has $10. Explain.

5 men dig 5 holes 5 feet deep in 5 hours. How long will it take one man to dig a half a hole?

What five-letter word becomes shorter when you add two letters to it?

A closed bag contains 3 green hats and 2 red hats. Rudy, Trudy, Judy all close their eyes, take a hat, put it on, and close the bag. When they open their eyes, Rudy looks at Trudy and Judy, but can’t deduce the color of his own hat. Trudy now tries to deduce her own hat’s color but can’t be certain. What color is Judy’s hat?

How can you measure 9 cups of water using a 4-cup and 7-cup container?

If a centipede runs a 3-legged race in 2 minutes, how many seconds will it take an oyster to clip the whiskers off a walrus?

Replace the letters with digits to make a valid sum. Each letter represents a different digit.

Arrange 5 pennies, 5 nickels, 5 dimes, 5 quarters and 5 half-dollars to make the row and column sums correct. Rows and columns are automatically marked with a check when the sum is correct, even if individual values are out of place. There may be more than one solution.

"New Game" creates a new game.
"Reset" restarts the current game.

Click on any colored shape to remove that tile from the board and create an empty space. Clicking on any tile next to the empty space slides that tile into the empty space. Continue to create the arrangement of your choice. Finally, click on the removed tile to replace it and complete the arrangement.

"Shuffle" randomly shuffles all the tiles.