Dividing Five Diamonds Equally

How can five people divide a bag of five diamonds equally without cutting them while still leaving one diamond remaining in the sack?

Give four of the lucky folks a diamond each, then give the fifth person the bag with the remaining diamond still inside.

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Next in the Sequence

Here is a series of numbers. What is the next number in the sequence?

1
11
21
1211
111221
312211

13112221

The next number in the series counts the previous numbers. Thus the first number is 1, which is one 1, or 11. To describe 11, you have two 1’s, or 21. Now you have one 2 and one 1, so the next number is 1211. The solution is to continue describing the previous number using only numbers.

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Amber Knits and Fauna Worry

Find a single letter that replaces the first letter in the two words of each row to make two new words. What word is formed by combining the new letter of each row?

For example: PLANK _ BRISK

The new letter is F, making FLANK and FRISK. And F would be the first letter of the answer.

AMBER _ KNITS
FAUNA _ WORRY
WARNS _ AERIE
FEMUR _ GAILY

1. U – UMBER and UNITS
2. S – SAUNA and SORRY
3. E – EARNS and EERIE
4. D – DEMUR and DAILY

The new word is USED.

Posted in Brain Teasers

I Am Worthless

I am worthless, yet when added to others I add worth.
I confounded the ancient Greeks, yet I changed men’s understanding.

What am I?

0 (Zero).

Zero is nothing, yet when you add zeroes to a number like 1, it becomes 10, 100 or 1,000.

The ancient Greeks did not have a name for zero and did not use a placeholder. They seemed unsure about the status of zero as a number, philosophizing about how nothing could be something. Once zero was added, it allowed for more mathematical understanding.

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Jim’s Canoeing Adventure

Jim was canoeing on a lake when a sudden thunderstorm blew in tipped his boat. He swam to a rocky island about a mile from his family’s cottage and found a small, abandoned shack. Inside was an old kerosene lamp and a few matches. All the wood on the island was too damp to burn and the lamp was his only means of signaling for help but it only held an inch of kerosene, not enough to reach its short wick. How did he get the lamp burning to summon help?

Knowing kerosene and water wouldn’t mix and kerosene is less dense than water, he dipped the lamp in the lake and filled it with enough water so the kerosene rose to the top to cover the wick. The lamp was still burning an hour later when a motorboat rescued him.

Posted in Brain Teasers

Don’t Get a Goat

On a game show there are three closed doors – one hides a car and the other two conceal a goat. The contestant selects a door, which remains closed, and the host, knowing where the car is hidden, reveals a goat behind one of the remaining two doors. The contestant is then given the option to switch doors or stay with the one they originally selected. What should the contestant do to have the best chance of winning the car?

The contestant should switch doors, which doubles the chance of winning the car. Initially there is a 2/3 chance of picking a goat, but once the other goat is revealed, switching to remaining door gives the contestant a better chance of winning the car. This is known as the Monty Hall Problem and can be very unintuitive.

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Broken Before Use

I am broken before you use me,
I brighten your day until I die.

What am I?

Glow sticks that you have to break to start glowing, then they fade out (die).

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Give Me Drink and I Die

Feed me and I live, give me drink and I die. What am I?

Fire.

Posted in Riddles

Numbers Map

Arrange the numbers from 1 to 8 in the following sequence.

     a
  b  c  d
  e  f  g
     h

Each number must not be diagonally or directly adjacent to any number directly before or after it.

For example, 2 can only be placed in one spot.

     2
  x  x  x
  x  1  x
     x

Here are two solutions (there might be more).

    7
3   1   4
5   8   6
    2

    2
5   8   6
3   1   4
    7
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Only At Rest Do They Touch the Ground

Two legs I have and this will confound, only at rest do they touch the ground. What am I?

A wheelbarrow.

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