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 Most Precious Commodity

What is the most precious commodity?
That which when needed seemingly is never enough,
Yet otherwise can be boringly plentiful.
While waking is oft dreamt of,
Whilst pining can scarcely be thought of.
For beings, is allotted in finite but indefinite quantity.
The more that’s given, the more is wasted.
Freedom is akin though this is something more simple,
Not related to virtue or sin.
Unless perhaps, without freedom, or its limit.

What is it?

Time.

(Thanks for submitting this one Duke)

Posted in Riddles
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Twenty One Points Divide And Dance

Twenty one points divide and dance,
Twirling and leaping about,
Ladies, Romans and knights of France,
Craving a victor’s rout,
Wrought of wood, ivory or bone,
An exciting yet vicious pursuit,
Ancient, forbidden and crooked,
All in search of the loot.

A die. The standard die has 21 pips (or points), divided up on the six sides of the die which dance around when rolled. Ladies, knights and Romans all played dice as a pastime (though not together). Dice can be made of wood, ivory and bone, among other materials. Dice have been used in Asia since before recorded history and many governments tried unsuccessfully to outlaw the game. Professional gamblers were common and often used loaded dice. Desperate German chaps even bet their own liberty on a single roll of the dice.

Posted in Riddles

Sentca

Four words can be made from the letters below. What are the words?

S E N T C A

1. ENACTS
2. ASCENT
3. STANCE
4. SECANT

Posted in Brain Teasers

The Ants Go Marching

Three ants are walking in the same direction. The first ant has two ants behind him, the second ant has one in front and one behind, but the third ant has one in front and one behind too. How is this possible?

The ants are in a circle. Lets say the ants are A, B and C. A has has B and C behind him, B has A in front and C behind, and C has B in front and A behind.

Posted in Brain Teasers

Rainbow Neighborhood

There was a neighborhood of one-story houses.
One was red and everything in the house was red.
Another was purple and everything in the house was purple.
Yet another was yellow and everything in the house was yellow.
Still another was blue and everything in the house was blue.
In the green house everything was green,
and in the gray house everything was grey.

What color were the stairs in the yellow house?

There are no stairs in any of the houses because they only have one story.

Posted in Brain Teasers

I Drive Men Mad

I drive men mad
For love of me,
Easily beaten,
Never free.

Gold.

Posted in Riddles

In Your Body Free the First Two Times

What is in your body for free the first and the second time but the third time you have to buy yourself?

Your teeth. You get baby teeth and adult teeth as part of the life package, but once you lose those you get to pay for dentures (or scare small children with your sunken face).

Posted in Riddles

Speaks Without Words

What is it that speaks without any words?
And can be loudly and distinctly heard?
Will drive away friend, and foe alike.
And is enough to make a stolid man’s face alight?

Flatulence.

Posted in Riddles

A Treasure to Many

A necessity to some, a treasure to many,
I’m best enjoyed among pleasant company.
Some like me hot, some like me cold.
Some prefer mild, some like me bold.

What am I?

Coffee.

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