I Turn Around Once

I turn around once,
What is out will not get in.
I turn around again.
What is in will not get out.

What am I?

A key.

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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

Your Father’s Sister’s Sister-in-law

What relation would your father’s only single sister’s sister-in-law be to you?

Your mother.

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A Smiling Guard

Two guards were on duty outside a barracks. One faced up the road to watch for anyone approaching from the North. The other looked down the road to see if anyone approached from the South. Suddenly one of them said to the other, “Why are you smiling?”

How did he know his companion was smiling?

They were facing each other. As to why his companion was smiling, the world may never know.

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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.

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You Hold My Tail

You hold my tail while I fish for you. What am I?

A fishing net.

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What Once Was Red Is Black Instead

Tear one off and scratch my head, what once was red is black instead. What am I?

A match. You tear a match out of a matchbook and scratch the head to light it, then the red tip turns black from the flame.

This is an exact duplicate of Tear One Off and Scratch My Head but I’m leaving it to avoid broken links.

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You’re Halfway There

You’re standing 11 feet away from a doorway and with each step you move halfway to the doorway. How many steps will it take for you to get to the doorway?

Technically, the answer is infinity. If you keep going halfway, you’ll never actually make it to the doorway.

But in practice, after 10 steps you’ll be 1/8th of an inch to the doorway and anyone behind you would say to stop being a baby and take a real step through the doorway already.

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What Goes Up And Down But Doesn’t Move?

What goes up and down but doesn’t move?

A staircase. They go up and down, but you’re the one moving.

Posted in Riddles

Ancient Arabic

I’m Arabic, but if you speak English, you probably use me every day.

What am I?

The Arabic numerals, 1, 2, 3, etc.

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