Which Coin is Counterfeit?

You are given eight coins and told that one of them is counterfeit. The counterfeit one is slightly heavier than the other seven. Otherwise, the coins look identical. Using a simple balance scale, how can you determine which coin is counterfeit using the scale only twice?

First weigh three coins against three others. If the weights are equal, weigh the remaining two against each other. The heavier one is the counterfeit. If one of the groups of three is heavier, weigh two of those coins against each other. If one is heavier, it’s the counterfeit. If they’re equal weight, the third coin is the counterfeit.

Posted in Brain Teasers

Dwarves and Snow White

The dwarves and Snow White sit down for a bite.
How fast can you guess what she serves her guests next?

Seven Seconds

Posted in Riddles

Stocking the Shelves

Alfred and Bill are clerks at the local grocery store. Alfred can stock a shelf in 20 minutes, but Bill is new and takes 30 minutes. How long would it take for them to stock a shelf together?

Working together they can stock a shelf at a rate of 1/20 + 1/30 (or 5/60) per minute. They’ll finish in 12 minutes

Posted in Brain Teasers

Lucky Number Seven

How is 7 different from the rest of the numbers from 1-10?

7 (seven) is the only one with two syllables.

Posted in Brain Teasers

A Great Woman

The first two letters of this English word refer to a male, the first three refer to a female, the first four to a great man and the whole word is a great woman.

What is the word?

Heroine (he, her, hero)

Posted in Riddles

Thanks, You’re Fired

A man is leaving on a business trip and stops by his office on the way to the airport. The night watchman stops him and says, “Sir, don’t take that flight. I had a dream last night that your plane would crash and everyone would die!” The business man cancels his trip and sure enough, the plane crashes, killing all the passengers. The man gives his watchman a $10,000 reward for saving his life, then fires him. Why?

Because his night watchman was sleeping on the job.

Posted in Brain Teasers

Split Itself

What can split itself
before splitting something else?

Lightning. It looks like it’s splitting apart in the sky, and trees are split in half when struck by lightning.

By Sef Daystrom

Posted in Riddles

Leaving Home

A man leaves home, turns left, goes straight, turns left again, goes straight and turns left once more then returns home and there’s another man with a mask on. What’s going on?

A baseball game.

Posted in Brain Teasers

How Can Four Be Half of Five?

How can the number 4 be half of FIVE?

Beginning with FIVE, take away the F and E (half of the letters), leaving IV, which is the Roman numeral for four.

Posted in Brain Teasers

Two Plus Two Equals Four

Each letter represents a different digit. Any digit can be used, but zero can never start a word. Given W = 2 and R = 6, what do the rest of the letters represent?

  TWO
+ TWO
------
 FOUR

F = 1
O = 8
R = 6
T = 9
U = 5
W = 2

  928
+ 928
-----
 1856
Posted in Brain Teasers