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.

Posted in Brain Teasers

A Big Pizza Pie

To get the most pizza, should you order two 12″ pizzas or one 18″ pie?

One 18″, with ~255 sumptuous square inches. Two 12″ pizzas would only give you ~226 square inches.

Note: The area of a circle is = πr2.

Posted in Brain Teasers

I Am What Remains

I am what remains of what
was once a living whole,
dug in deep, protruding, though,
and unobtainable.

A stump.

By Sef Daystrom

Posted in Riddles
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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

Two Hands But Can’t Clap

I have two hands but I cannot clap. What am I?

A clock.

Posted in Riddles
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Willow’s Broken Keyboard

Willow’s keyboard is acting up. The a, e, i, o and u keys don’t work and the space key is misbehaving as well. Can you decipher these common sayings they typed?

tfsghttfmnd
ctnsspkldrthnwrds
hnstysthbstplcy
sycmsyg

Out of sight, out of mind
Actions speak louder than words
Honesty is the best policy
Easy come, easy go

Posted in Brain Teasers

The Longest Pregnancy

A baby was born four years after its parents died in a car crash. How was this possible?

Amazingly, this actually happened. The parents died in a crash crash and their parents fought for the rights to the four frozen embryos left by their late children. After a surrogate pregnancy, the baby was born with DNA matching their deceased parents.

Posted in Brain Teasers

Days Before August 17th

How many days before August 17th is it, if fifty days ago, it was four times as many days since March 30th?

18 days or July 30th.

17 August – 18 days = 30 July.
30 July – 50 days = 10 June.
10 June – 30 March = 72 days, which equals 4 × 18.

Posted in Brain Teasers

Many Feathers To Help Me Fly

I have many feathers to help me fly. I have a body and head but I’m not alive. Your strength determines how far I go. You can hold me in your hand, but I’m never thrown.

What am I?

An arrow.

Posted in Riddles

A Lady’s Delight

Lovely and round,
I shine with pale light,
Grown in the darkness,
A lady’s delight.

What am I?

A pearl. They’re formed in clams, which are of course dark.

Posted in Riddles