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

Lives in the Corner

What lives in the corner but travels the world?

A postage stamp.

Posted in Riddles

Where I Never Was

You saw me where I never was and where I could not be. And yet within that very place, my face you often see. What am I?

A reflection

Posted in Riddles

Blast Paper Box Bank

Here are two groups of words.

A. blast, paper, box, bank
B. juice, bag, cradle, carpet

Which word from Group B belongs with the words from Group A?

Bag. All of the words in group A can begin with the word sand.

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Throw It Out To Use

What do you throw out to use and take in when you’re done?

An anchor.

Posted in Riddles

Surf, School, Room

What word can be added before or after these words to make a new word or phrase?

Surf, School, Room

Board. Surf board, school board (or maybe boarding school), board room.

Posted in Riddles

What Does He Weigh?

The owner of the butcher shop is five foot ten inches tall, has brown hair and wears size 11 1/2 shoes. He is married and has two children, one boy and one girl. What does he weigh?

Meat. The rest of the details were merely distractions. Butchers weigh meat at a butcher shop.

Posted in Brain Teasers

Fix This Roman Numeral Equation

This Roman numeral equation is wrong, but you can fix it without changing any of the elements of the equation. How is this possible?

I + XI = X

Look at it upside down. Instead of changing the equation, you can change your perspective.

This is from Dan Brown’s novel, Origin.

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Seeds on the Outside

What fruit has seeds on the outside?

A strawberry.

Posted in Riddles

Sisters and Brothers

My daughter has as many sisters as she has brothers. Each of her brothers has twice as many sisters as brothers. How many sons and daughters do I have?

Four daughters and three sons. Each daughter has 3 sisters and 3 brothers, and each brother has 2 brothers and 4 sisters.

To figure it out mathematically, you could use the following two equations where G = the number of girls and B = the number of boys:
G – 1 = B
2(B – 1) = G

Solving for G gives you 4 and plugging that in to G – 1 = B gives you a B of 3.

Posted in Brain Teasers