Code in the Cold

Last winter I found myself locked out of my house because I couldn’t remember the 5-digit code to open the garage door. I used the following facts to get inside.

1. The second and third digits add up to 9.
2. The first digit is equal to the second digit cubed.
3. The sum of the third and fifth digits is the smallest number with exactly five divisors.
4. The fourth digit is equal to 6 times the second-to-last digit.
5. None of the digits repeat.

What was the code?

82709

If we label each digit a, b, c, d and e, we get the following equations.
1. b + c = 9
2. a = b3
3. c + e = 16 (since 16 is the smallest number with five divisors – 1, 2, 4, 8 and 16).
4. d = 6 * d (The fourth and second-to-last digits are the same number, meaning d must be zero to satisfy the equation)
5. b must be zero, one or two (b can’t be three because that makes a=27, which isn’t a single digit). Zero and one result in duplicate digits (00907 and 11808 respectively) so the only remaining value for b is 2, giving us 82709 and warmth.

Posted in Brain Teasers

Sits in the Corner

I sit in a corner and travel around the world. What am I?

A stamp.

This is nearly a duplicate of Lives in the Corner.

Posted in Riddles

Bowl That Can’t Be Filled

I am as round and deep as a bowl, but all the world’s water couldn’t fill me up. What am I?

A sieve.

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What Binds These?

What word binds all of these together?

Burglar
Fat
Copy
Bag
Nap

Cat.

Cat burglar
Fat cat
Copy cat
Let the cat out of the bag
Cat nap

Posted in Riddles

Pronounced Right or Wrong

What word when pronounced wrong is right but when pronounced right is wrong?

The answer is the word “wrong”. When it’s pronounced “wrong” (rhyming with song) that’s the correct pronunciation. However, if you were to pronounce the word as “right” (rhyming with night) that would be an incorrect pronunciation and be wrong.

Posted in Riddles

Black We Are And Much Admired

Black we are and much admired,
men seek us if they are tired,
We tire the horse, comfort man,
guess this riddle if you can.

Coal.

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A Most Unusual Paragraph

This is a most unusual paragraph. How quickly can you find out what is so unusual about it? It looks so ordinary you’d think nothing was wrong with it – and in fact, nothing is wrong with it. It is unusual though. Why? Study it, think about it, and you may find out. Try to do it without coaching. If you work at it for a bit it will dawn on you. So jump to it and try your skill at figuring it out. Good luck! Don’t blow your cool!

The most common letter in the English language, the letter e, is not found in the entire paragraph.

Posted in Riddles

All Like Me Would Now Retire

I work hard most every day,
Not much time to dance and play,
If I could reach what I desire,
All like me would now retire.

What am I?

A doctor. They work hard to eradicate illness, but if they ever succeeded, they would no longer be needed. Hey, that even rhymed!

Posted in Riddles

Twice As Many Women As Children

At a party of thirty-five people there are twice as many women as children and twice as many children as men. How many of each are there?

20 women, 10 children and 5 men.

To figure it out, let m be the number of men and you get this equation:

4m + 2m + m = 35
7m = 35
m = 35 ÷ 7
m = 5

Posted in Brain Teasers

To Protect Our King From A Foe’s Attack

The eight of us go forth not back to protect our king from a foe’s attack. What are we?

Pawns in a chess game. There are eight pawns and they are only permitted to move forward, not backward and the primary objective in chess is to protect the king.

Posted in Riddles