Jim and Wanda’s Apples

Jim and Wanda both have some apples. If Jim gives Wanda an apple, they will both have the same number of apples. However, if Wanda gives Jim an apple, Jim will have twice as many as Wanda. How many apples do Jim and Wanda each have?

Jim has 7 apples and Wanda has 5 apples.

Posted in Brain Teasers

Subtracting Ten From A Hundred

How many times can you subtract 10 from 100?

Only once. The next time you’d be subtracting 10 from 90.

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The Ants Go Marching

Three ants are walking in the same direction. The first ant has two ants behind him, the second ant has one in front and one behind, but the third ant has one in front and one behind too. How is this possible?

The ants are in a circle. Lets say the ants are A, B and C. A has has B and C behind him, B has A in front and C behind, and C has B in front and A behind.

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

Always Old, Sometimes New

Always old, sometimes new.
Never sad, sometimes blue.
Never empty, sometimes full.
Never pushes, always pulls.

What am I?

The moon. The moon has been around for quite some time, but there’s a “new” moon every month or so. A Blue moon is a rare event. The moon is a body of rock, so it’s never empty, but we do see what we call a full moon some nights. And the moon’s gravity “pulls” on the ocean to create low and high tides, but it doesn’t push anyone around because it’s a friendly fellah.

Posted in Riddles
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Hear a Lot, Say a Lot

I hear a lot
And I say a lot
Few ever look for me
And even fewer ever hear me
I hide in plain sight
Whether its day or night
To help is all I want
But most like to bend me
And as if they had a wand
Never again shall anyone find me
They do this to control
Without realizing the high price of a soul
But when I’m least expected
They’d rather be protected
For there shall be no place to hide
What am I?

The truth.

Posted in Riddles
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Four Against the Masses

We are four against the masses. We are trying to find the one who is the whole package. We sigh, we laugh, we frown while we hope that the next one will be the one. Who are we?

Four orphaned siblings. It seems like there may be a better answer than this. If you have one, please add a comment.

Posted in Riddles

Wait 27 Days Or See It Every Day?

You could wait 27 days or you could see it everyday. What is it?

The moon. Even though the true moon cycle is about 29.5 days, it takes 27 days, 7 hours, and 43 minutes for our Moon to complete one full orbit around Earth. Thus you can see the full moon every 27 days or you can moon yourself every day in the mirror. Not that you’d want to. Does anyone moon themselves? Can’t say as I’ve ever had the “pleasure”.

Posted in Riddles

False Positive HIV Test

Imagine an HIV test that is 95% accurate (false positive rate of 5%) and around 2% of the tested population is infected with HIV. What is the probability that you actually have HIV when your test comes back positive?

29%

To read more about this, see the False Positive Paradox page on Wikipedia.

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Word Party

You watch a group of words going to a party. A word either enters through one of two doors or is turned away by the guards. ‘HIM’ goes through door number one and ‘BUG’ goes through door number two. ‘HER’ is turned away. ‘MINT’ and ‘WEAVE’ go in through door one, ‘DOOR’ and ‘CORD’ take door two and ‘THIS’ and ‘That’ aren’t allowed in.

What determines whether a word can enter and which door they must use?

Door number one is for words composed entirely of capital letters written using only straight lines, such as A, E, F, H, and I. The entire set of letters allowed through door number one are AEFHIKLMNTVWXYZ. Door number two, as might be expected, is for words with capital letters that have a curve, including BCDGJOPQRSU. Any words composed of both straight and curved letters (or lowercase letters) are not allowed in. The word ‘THAT’ would have been sent through door number one, if the letters had been capitalized.

Posted in Brain Teasers