Mental Calculations

Perform this calculation in your head, mentally adding the numbers as quickly as you can. Start with 1000 and add 40. Now add 1000. Add 30 to that, then add another 1000. Now add 20 to that result. Add another 1000 and finally, add 10 to that. What is the total?

4,100. If you got 5,000 you’re not alone. 96% of test subjects get the wrong answer.

Posted in Brain Teasers

At Birth It Can’t Start Nor By Death Is It Ended

More precious than gold, but cannot be bought,
Can never be sold, only earned if it’s sought,
If it is broken it can still can be mended,
At birth it can’t start nor by death is it ended.

Friendship. It is more precious than gold to have a genuine friend, and true friendship cannot be bought or sold, only earned. When a friendship is broken it can be fixed and infants aren’t able to make friends until they’re older, but death can’t end it. Love doesn’t work as an answer because a friendship requires two people to interact, while parents love their children as soon as they’re born.

Posted in Riddles

The Greatest God

The Pharoah asked, “Who is the greatest god?”

“I am not,” said Horus.
“Anubis is,” said Isis.
“Isis is lying,” said Anubis.

Only one god was telling the truth and the other two were lying.

Who really is the greatest god?

Horus is the greatest

“I am not,” said Horus = LIE
“Anubis is,” said Isis = LIE
“Isis is lying,” said Anubis = TRUE

Posted in Brain Teasers

Bricks to Finish a Building

How many bricks does it take to finish a brick building?

One (the last one is the only one that can finish the building).

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.

Posted in Brain Teasers

Two Plus Two Equals Four

Each letter represents a different digit. Any digit can be used, but zero can never start a word. Given W = 2 and R = 6, what do the rest of the letters represent?

  TWO
+ TWO
------
 FOUR

F = 1
O = 8
R = 6
T = 9
U = 5
W = 2

  928
+ 928
-----
 1856
Posted in Brain Teasers

Fall Crop

What three or four-letter word belongs between the word on the left and the word on the right so that the first and second, and second and third words form a compound word or phrase?

For example: FOOT _ _ _ _ PARK would be BALL, or FOOTBALL and BALL PARK.

1. FALL _ _ _ CROP
2. KNEE _ _ _ SIZE
3. BOARD _ _ _ _ WAY

1. OUT – FALLOUT, OUTCROP
2. CAP – KNEECAP, CAPSIZE
3. WALK – BOARDWALK, WALKWAY

Posted in Brain Teasers

What Times Seven Is All Fours?

What is the smallest integer that is all 4s when multiplied by 7?

63,492 × 7 = 444,444

Posted in Brain Teasers

I Was Not Born

I was not born, but I am here.
I have no name, but I am given many.
I was made by science and life.

What am I?

A clone.

Posted in Riddles
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No Ears and More Than One Eye

I have no ears, but more than one eye,
Cut me in half, I won’t cry,
Leave me alone and I will die.

What am I?

A potato. The roots growing out of a potato are called eyes, when you cut a potato in half it doesn’t produce any moisture and if you leave a poor potato to its own devices, it will die.

Posted in Riddles