Rotating Coins Around Coins

You have two coins of equal size on a table, situated end to end vertically. If you roll the top coin around the bottom coin until it returns to its original position, how many times will it have rotated?

Twice. See this video for more details.

Posted in Brain Teasers

Number Abbreviations

What do these represent?

24 = HiaD
26 = LotA
7 = DotW
9 = LoaC
12 = SotZ
88 = PK

24 hours in a day
26 letters of the alphabet
7 days of the week
9 lives of a cat
12 signs of the Zodiac
88 piano keys

Posted in Brain Teasers

The Average of Three

There are three numbers. The first two are 2/3 and 3/4.

What does the third number have to be to make the average of all three be 2?

4 7/12

In order for the average of three numbers to be 2, they must all add up to 6. That gives you this equation:
2/3 + 3/4 + n = 6

Solve for n = 55/12, or 4 7/12.

Posted in Brain Teasers

In Oven But Not Baked

What must be in the oven yet can not be baked?
Grows in the heat yet shuns the light of day?
What sinks in water but rises with air?
Looks like sand, but is fine as hair?

Yeast.

Posted in Riddles

Too Much For One

I am too much for one, enough for two, but nothing to three. What am I?

A secret.

Posted in Riddles

Rearrange My Letters To Be Clean

Rearrange these letters into something you can clean with.

boas

soap (by flipping the b upside down, similar to how IHOP became IHOb)

Posted in Brain Teasers

Al and Fred’s Car Wash

Al washes a car in 6 minutes. Fred washes the same car in 8 minutes. How long will it take them to wash the car together?

There isn’t enough information, thus there’s no one, right answer. (As frustrating as that may be)

This is from the TV show Boy Meets World, season 1 episode 12.

Posted in Brain Teasers

Asks But Never Answers

What asks but never answers?

An owl.

Posted in Riddles
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Kevlar, Fire Escapes and Wipers, Oh My!

What do computer compilers, kevlar, fire escapes and windshield wipers all have in common?

They were all invented by women.

A variation of this brain teaser includes laser printers (they were invented by Gary Starkweather) and bulletproof vests (invented by Casimir Zeglen using silk, though modern vests use Kevlar, so it’s halfway right).

Posted in Brain Teasers

A Circled of Joined Hands

You dance in a circle of joined hands,
And though they spin away I can always see your face,
In the world, no matter where I am,
One look at you and I know my place.

What am I?

A clock.

An analogue clock is a circle, and the hands of a clock are joined at the middle.
The hands can point away from you, but the clock face is always visible.
No matter where you are in the world, you can probably find a clock.
“One look at you and I know my place…in time!”

Thanks to Helena for creating this and sending it in.

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