The Bookworm

A bookworm eats from the first page of an encyclopedia to the last page in a straight line. The encyclopedia consists of ten 1000-page volumes and is sitting on a bookshelf in the usual order. Not counting covers, title pages, etc., how many pages does the bookworm eat through?

        __                             __
      B|  |                           |  |F
      A|1 |...........................|10|R
      C|  |                           |  |O
      K|  |                           |  |N
       |__|                           |__|T
      -------------------------------------

On a book shelf the first page of the first volume is on the “inside”, so the bookworm eats only through the cover of the first volume, then 8 times 1000 pages of Volumes 2 – 9, then through the cover to the 1st page of Vol 10 for a total of 8,000 pages.

Note: The question asks how many pages, not how many sheets of paper.

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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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You Twirl My Body

You twirl my body but I keep my head up high.
When I go in I keep things tight.

What am I?

A screw.

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Dry As a Bone

Milton was out for a walk when it started to rain. He did not have an umbrella and wasn’t wearing a hat. His clothes were soaked, yet not a single hair on his head got wet. How did this happen?

Milton sadly suffers from alopecia, more commonly known as baldness. The old coot was as bald as a ping pong ball, leaving not a single hair on his head to get wet.

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Six Letter Word

What 6-letter word has the same pair of letters in spots 1 and 5, a different pair in spots 2 and 6 and contains a ‘u’ in between?

church, delude, inulin or recure

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Evianna’s New Love Interest

Evianna meets a man while attending her mother’s funeral. She becomes infatuated with him and he reciprocates the interest, but he leaves the funeral without giving her any contact information. She tries to locate him but is unsuccessful. Several days later she kills her sister.

Why did she do it?

Because she’s a psychopath. She killed her sister because she hoped the man would attend the funeral and she would get to see him again. This is one brain teaser that is probably best that you don’t get the correct answer. If you knew the answer right away and thought it was obvious, you may want to talk to someone.

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What Everleigh Likes

Everleigh likes knights but not batteries, writing but not typing and to listen but not to sing. Does she like an unknown or a famous author?

Unknown. Everleigh likes words with silent letters.

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What Letter Comes Next?

The letters in this series are ones that don’t begin something. Figure out what that something is, and what letter comes next.

B E J ?

Q. The thing they don’t begin is states in the United States of America. The final three letters in the series are X, Y and Z.

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A NA A SA A

A NA A SA A A

What comes next in the series?

E. Each item is the first letter(s) of one of the seven continents:

1. Asia
2. North America
3. Africa
4. South America
5. Australia
6. Antarctica
7. Europe

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I Drift Forever With The Current

I drift forever with the current
down these long canals they’ve made
Tame, yet wild, I run elusive
Multitasking to your aid.
Before I came, the world was darker
Colder, sometimes, rougher, true
But though I might make living easy,
I’m good at killing people too.

Electricity (or lightning).

Posted in Riddles