Alfred’s Tough Cash Request

Alfred is at the bank to cash his $200 check. He tells the cashier he would like some one dollar bills, ten times as many two dollar bills and the rest in fives.

How many of each denomination does the cashier need to give Alfred?

Five $1 bills, 50 $2 bills and 19 $5 bills.

We know that in order to give the rest of the amount in fives, the sum of the one and two dollar bills needs to be divisible by five (i.e. end in 0 or 5).

If we start with a single one dollar bill, we’d need ten two dollar bills to satisfy the request, making $21. But we need a sum that is divisible by 5. So we keep going up, like so:

$1 + $2 * 10 = $21
$2 + $2 * 20 = $42
$3 + $2 * 30 = $63
$4 + $2 * 40 = $84
$5 + $2 * 50 = $105 (Aha! It’s divisible by 5)
$6 + $2 * 60 = $126
$7 + $2 * 70 = $147
$8 + $2 * 80 = $168
$9 + $2 * 90 = $189

So the only option that works is 5 $1 bills and 50 $2 bills, leaving $95 (95 / 5 = 19) to be paid out in 19 fives.

Alfred is one tough customer.

Posted in Brain Teasers

Sum of 22

Fill in numbers such that the sum of each 3-character row is 22 while the sum of all five numbers is 30.

a
bcd
e

The problem works out to a set of three equations:
b + c + d = 22
a + c + e = 22
a + b + c + d + e = 30

Solving for c = 14, leaving d = 8 – b and e = 8 – a. In other words, c must be 14, but the other two numbers just have to add up to 8. The requirement that they be unique rules out 4 + 4, so you’re left to choose from the following combations for b + d and a + e:
0 + 8
1 + 7
2 + 6
3 + 5

Posted in Brain Teasers

A Final Screech

I saw a strange creature,
Long, hard, and straight,
Thrusting in a round, dark, opening,
Preparing to discharge its load of lives,
Puffing and squealing noises accompanied it,
Then a final screech as it slowed and stopped.

Note: This may not be appropriate for younger ages.

A subway train.

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Here Comes My Wife and Daughter

Two men are standing on one side of a bridge and two women are approaching them. One of the men says, “Here comes my wife and daughter” to which the second man replies, “Here comes my wife and daughter”. If they have not married the same woman and the women aren’t pregnant, how is this true?

The men are widowers and married each others’ daughter.

Posted in Brain Teasers

What Has Wheels and Flies?

What has wheels and flies, but is not an aircraft?

A trash truck. I heard this one when I was a kid. Still a classic!

Posted in Riddles

Special Two Letter Combinations

What do these three letter combinations have in common?

DE
HI
MN

Hint: These combinations don’t have it in common.

AK
IN
WY

They are the only three US state abbreviations whose two letters are next to each other in the alphabet.

DE – Delaware
HI – Hawaii
MN – Minnesota

Posted in Brain Teasers

Two Halves And a Whole

Complete the three missing words in the sentence, with the first two words combining to form the third word.

For example:

The prime minister ____ the meeting, even though the ____ was technically the ____ official.
The three missing words would be RAN, KING, and RANKING.

Now solve this one:

When she broke her ____ showing off at the ____ of the ski run, Arya became a ____ among her friends.

LEG, END, LEGEND

When she broke her LEG showing off at the END of the ski run, Arya became a LEGEND among her friends.

Posted in Brain Teasers

Black Coat Rebus

What does this represent?

 black
-------
 coat

Black overcoat.

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Jim’s Canoeing Adventure

Jim was canoeing on a lake when a sudden thunderstorm blew in tipped his boat. He swam to a rocky island about a mile from his family’s cottage and found a small, abandoned shack. Inside was an old kerosene lamp and a few matches. All the wood on the island was too damp to burn and the lamp was his only means of signaling for help but it only held an inch of kerosene, not enough to reach its short wick. How did he get the lamp burning to summon help?

Knowing kerosene and water wouldn’t mix and kerosene is less dense than water, he dipped the lamp in the lake and filled it with enough water so the kerosene rose to the top to cover the wick. The lamp was still burning an hour later when a motorboat rescued him.

Posted in Brain Teasers

I Can Kill People

I can kill people, or cause great pain.
You eat me.
I can mean you’re crazy.
I hold things together.
I help climbers stay safe.
I can replace a swear.
And I’m on a violin.

What am I?

Nuts.

People with nut allergies can die from eating nuts. Being hit in the nuts hurts (I speak from experience. Painful, painful experience). You eat nuts (unless you’re allergic, in which case you should run away). If someone says you’re nuts, it doesn’t mean you’re a peanut or an almond. Nuts and bolts hold things together. A climber’s nut or chock wedges into a rock. Instead of swearing, you can say, “Aww nuts!”. And finally, the nut on a violin is a small piece of hard material that supports the strings.

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