Bank Wait Times

Suppose a small bank has one teller and customer transactions take 10 minutes on average. With 5.8 customers arriving per hour, what is the expected wait time? What would it be if you added a second teller?

With one teller, customers will wait nearly five hours on average. But adding a second teller makes the wait go down to 3 minutes.

Thanks to John D. Cook for this one.

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Measured But Not Seen

What can be measured but not seen?

Time. Or my toes when I’ve had one too many donuts…

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Roads Without Cars

Where will you find roads without cars, forests without trees and cities without houses?

On a map.

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Nine Matchbox Sticks To Ten

I have nine matchbox sticks and would like to make ten. How do I do it?

Arrange the nine matchbox sticks like so to make the shape of the number ten:

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Posted in Brain Teasers

One Tooth To Bite

One tooth to bite,
He’s the forest’s foe.
One tooth to fight,
As all Norse know.

What is it?

An axe.

Posted in Riddles

Holds Fast To The Center Of Everything

There is one word that stands the test of time and holds fast to the center of everything. Though everyone will try at least once in their life to move around this word, but in fact, unknowingly, they use it every moment of the day. Young or old, awake or in sleep, human or animal, this word stands fast. It belongs to everyone, to all living things, but no one can master it. The word is?

Gravity.

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Which Coin is Counterfeit?

You are given eight coins and told that one of them is counterfeit. The counterfeit one is slightly heavier than the other seven. Otherwise, the coins look identical. Using a simple balance scale, how can you determine which coin is counterfeit using the scale only twice?

First weigh three coins against three others. If the weights are equal, weigh the remaining two against each other. The heavier one is the counterfeit. If one of the groups of three is heavier, weigh two of those coins against each other. If one is heavier, it’s the counterfeit. If they’re equal weight, the third coin is the counterfeit.

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What Gives Life and Love

What gives life and love, and is there till they die?
What can hide you and find you, heal you and feed you but should never give up on you?

A mother.

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Measures Out Time

I measure out time,
Until in time,
All is smashed into me.

What am I?

Sand

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Five Hundred Begins It

Five hundred begins it, five hundred ends it,
Five in the middle is seen;
First of all figures, the first of all letters,
Take up their stations between.
Join all together, and then you will bring
Before you the name of an eminent king.

DAVID (Roman numerals).

Posted in Riddles