Secure Spy Transfer

You are a spy and need to send an item to a contact in another country without letting anyone else have access to it. All unlocked items will be opened in transit. How can you send this item securely?

Place a lock on the item and send it to your contact. They will place their own lock on the package and return it to you. You remove your lock and send it back. When they receive it, they can unlock the package and retrieve the item.

Posted in Brain Teasers

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

Turning the Years Upside Down

What years from the 1900s and 1800s are the same year when read upside down?

1961 and 1881.

Posted in Brain Teasers

An Ancient Invention

What ancient invention allows people to see through walls?

A window.

Posted in Riddles

Scrambled Auctioned

What are two other words (anagrams) that can be made from the letters in “auctioned”?

1. Cautioned
2. Education

Posted in Brain Teasers

The Barber of Seville

The Barber of Seville shaves all men living in Seville.
No man living in Seville is allowed to shave himself.
The Barber of Seville lives in Seville.

Who shaves the Barber of Seville?

Nobody. The Barber of Seville is a woman. Female barbers are rare, but they exist.

And for more fun with barbers, check out the Barber paradox.

Posted in Brain Teasers

A U2 Concert

U2 has a concert that starts in 17 minutes and they must all cross a bridge to get there. All four men begin on the same side of the bridge. You must help them across to the other side. It is night. There is one flashlight. A maximum of two people can cross at one time. Any party who crosses, either 1 or 2 people, must have the flashlight with them.

The flashlight must be walked back and forth. It cannot be thrown and other tricks like that are not needed to solve the problem. The solution is simply a matter of allocating resources in a certain order. Each band member walks at a different speed. A pair must walk together at the rate of the slower man’s pace:

Bono: 1 minute to cross
Edge: 2 minutes to cross
Adam: 5 minutes to cross
Larry: 10 minutes to cross

For example: if Bono and Larry walk across first, 10 minutes have elapsed when they get to the other side of the bridge. If Larry then returns with the flashlight, a total of 20 minutes have passed and you have failed the mission.

This is one of my favorite brain teasers and I want to give you the satisfaction of figuring it out on your own. If you’re having a hard time, here’s a hint: There is a valid answer that doesn’t require tricks like throwing the flashlight or shining it backwards or having some other means of moving the flashlight.

There’s an assumption people often make that keeps them from solving this. Two members cross the bridge each time, but neither one of the two who crossed necessarily need to return. Think about how that would be possible. If you’re still stuck, use objects to simulate their movements. Use whatever you have laying around – pens, paper, erasers – and move them back and forth. Good luck!

Posted in Brain Teasers

The Hand of the Princess

A wise king devised a contest to see who would receive the Princess’ hand in marriage. The Princess was put in a 50 x 50 foot carpeted room. Each of her four suitors were put in one corner of the room with a small box to stand on. The first one to touch the Princess’ hand would be the winner and become the new King.

The rules were the contestants could not walk over the carpet, cross the plane of the carpet, or hang from anything; nor could they use anything but their body and wits (i.e. no magic, telepathy, nor any items such as ladders, block and tackles etc). One suitor figured out a way and married the Princess and became the new King. What did he do?

Asked the princess to touch his hand.

Posted in Brain Teasers

Where do the Numbers Belong?

Three numbers, 16, 14 and 38, need to be assigned to one of the rows of numbers below. Where do the numbers belong?

A06893
B1527211019
C71471117

Hint: This is not a mathematical problem. The numerical values are irrelevant.

The rows indicate the shape of the number. Row A is rounded, B is mixed and C is linear. Thus, 16 belongs in row B, 14 in row C and 38 in row A.

Posted in Brain Teasers

Not Many People Understand Me

My first three letters stores things. Not many people understand me. What am I?

Binary. Bin is a storage container and binary just 1s and 0s.

Posted in Riddles
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