Take Off My Clothes, Puts Its On

When I take off my clothes, it puts on its clothes.
When I put on my clothes, it takes off its clothes.

A clothes hanger.

Posted in Riddles

What are the Things?

In one day, 6 things.
In one week, 4 things.
In one month, 2 things.
In one year, 1 thing.

What are the things?

Odd numbers.

In a day, there are 6 odd hours: 1, 3, 5, 7, 9, 11 (ignoring 24-hour time).

In a week, there are 4 odd-numbered days: 1, 3, 5, 7

In a month, there are 2 odd weeks: 1, 3 (no month has 5 full weeks)

And in a year’s 12 months, there is 1 odd number: 1 (the 1 of 12).

I readily agree the year one is a stretch, but I didn’t write it :)

Posted in Riddles

Goes With a Car

What goes with a car, comes with a car, is of no use to a car, but the car can’t move without it?

Noise. The engine is usually the main culprit, but even electric cars make some noise from the tires on the road.

Posted in Riddles

777, 888 and 999

You are given the numbers 777, 888 and 999. Using the numbers once and adding, subtracting, multiplying or dividing, how can you make 999?

(7 x 7 x 7) + (9 x 9 x 8) + ((9 – 8) x 8) = 999
(77 + 7) + 888 + (9 + 9 + 9) = 999

If other operators were allowed, another solution would be 999 modulo (888 x 777). I’m sure there are more solutions.

Posted in Brain Teasers

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

What is the Five Digit Number?

What 5-digit number satisfies the following requirements?

1. No zeroes
2. First two digits are the same
3. Fourth digit is twice the first
4. Last digit is twice the third
5. Sum of all digits is 18

33264.

There are several ways of solving this. One way is to represent each spot with a letter, A – E.

Then you have these equations:

A = B
D = 2 * A
E = 2 * C
A + B + C + D + E = 18

By simplifying, you get:

4 * A + 3 * C = 18

Plug in values for A and C to find that A = 3 C = 2.

Posted in Brain Teasers

Twice in Eternity

I occur twice in eternity,
And I’m always within sight.

What am I?

The letter ‘t’.

Posted in Riddles
Tagged with

Complete the Word Square

A word square is a combination of words that can be spelled horizontally and vertically.

The most well known is called the Sator Square (in Latin):

S A T O R
A R E P O
T E N E T
O P E R A
R O T A S

What five words complete this word square?

I T C H E S
T _ _ _ _ _
C _ _ _ _ _
H _ _ _ _ _
E _ _ _ _ _
S _ _ _ _ _

Thrust, Crisco, Hussar, Escape and Stores.

Making this lovely word square below:

I T C H E S
T H R U S T
C R I S C O
H U S S A R
E S C A P E
S T O R E S
Posted in Brain Teasers

Three Lives Have I

Three lives have I.
Gentle enough to soothe the skin,
Light enough to caress the sky,
Hard enough to crack rocks.

Water.

Posted in Riddles

Three Children’s Names

Tom’s mother has three children. One is named April, one is named May. What is the third one named?

Tom

Posted in Brain Teasers