Making Lots of Shirts

In a textile factory, 5 machines take exactly 5 minutes to make 5 shirts. How many minutes will it take 100 machines to produce 100 shirts?

5 minutes. It takes each machine 5 minutes to make a shirt, so if you have all 100 machines running at the same time, they’ll produce the 100 shirts in 5 minutes.

Posted in Brain Teasers

Until I Am Measured

Until I am measured
I am not known,
Yet how you miss me
When I have flown.

Time.

Posted in Riddles

The More You Have, The Less You See

The more you have of it, the less you see. What is it?

Darkness.

Posted in Riddles

Three Lives Have I

Three lives have I.
Gentle enough to soothe the skin,
Light enough to caress the sky,
Hard enough to crack rocks.

Water.

Posted in Riddles

Cops Close Cellar Corpse

Replace the letters with numbers to make this a valid mathematical equation.

    COPS
   CLOSE
  CELLAR
  CORPSE
    CASE
+ COLLAR
--------
  RECTOR
    2730
   29704
  249918
  278304
    2104
+ 279918
--------
  842678
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.

Posted in Riddles
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A City in the Twilight

Half-way up the hill, I see thee at last, lying beneath me with thy sounds and sights — A city in the twilight, dim and vast, with smoking roofs, soft bells, and gleaming lights.

The Past (Longfellow).

Posted in Riddles

Easy To Touch

You have one of me and I’m easy to touch,
I’m hard to look at, but you can in a clutch.

Yet you’re told to watch me, or get your friends’.
I’m often referred to when you make amends.

You can throw me out but not away,
I cause many pain, every day.

What am I?

Your back. You have one and it’s easy to touch but hard to look it. A common phrase is to “watch your back” and it’s common to “have your friend’s back.” When apologizing, you often want to take back what you said. You can throw out your back, but you can’t throw it away. And back pain causes people pain every day.

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Canaries in the Cage

I am the owner of a pet store. If I put in one canary per cage, I have one bird too many. If I put in two canaries per cage, I have one cage too many. How many cages and canaries do I have?

Four canaries and three cages.

If you put one canary in each cage, you have an extra bird without a cage. However, if you put two canaries in each cage then you have two canaries in the first cage, two canaries in the second cage and an extra cage.

Posted in Brain Teasers

Snake Crossing

A man saw a snake crossing the road and swerved to crush it with his tires. All the street lights were off as well as the car’s headlights. There were no other lights on along the road.

How did the man see the snake?

It was during the daytime.

Posted in Brain Teasers