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  #21  
Old Oct 28th 2008, 09:25 AM
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Default Re: Brain Teasers & Riddles

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Originally Posted by Michael View Post
24 hour rule invoked...

Lev Tolstoy's Riddle

A group of harvestmen was asked to scythe two fields. The first field was twice the size of the other. Half of the day the whole group worked on the bigger field, in the afternoon the group divided into half. First group finished the whole field by the end of the day. The second group went to scythe the smaller field and worked untill the end of the day too. However a small piece of this field was left undone. The following day the rest of the field was scythed. It took the whole day to finish it by one harvestman. How many harvestmen were in the group?
There were 8 men in the original group. Yes?

Large field work = (1/2 day)(X men) + (1/2 day)(X/2 men)
Small field work = (1/2 day)(X/2 men) + (1 day)(1 man)
:. X/2 + X/4 = 2(X/4 + 1) = X/2 + 2
:. X/4 = 2
:. X = 8
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  #22  
Old Oct 28th 2008, 10:25 AM
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Michael Michael is offline
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Default Re: Brain Teasers & Riddles

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Originally Posted by dilettante View Post
There were 8 men in the original group. Yes?
Correct.

Quote:
Originally Posted by dilettante View Post
Large field work = (1/2 day)(X men) + (1/2 day)(X/2 men)
Small field work = (1/2 day)(X/2 men) + (1 day)(1 man)
:. X/2 + X/4 = 2(X/4 + 1) = X/2 + 2
:. X/4 = 2
:. X = 8
There are apparently several different solutions that produce the same answer of 8.

You're up!
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  #23  
Old Oct 28th 2008, 10:58 AM
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Default Re: Brain Teasers & Riddles

Here's insidious derivative from drgoodtrips riddle in post #10 (hopefully I won't misremember and screw this up):

There are two brothers; one is always honest, the other is always a liar. Furthermore (and this is where it gets interesting), the honest brother is perfectly accurate in all his knowledge: everything that is true, he believes to be true, everything that is false, he believes to be false. Similarly, the dishonest brother is perfectly inaccurate in his knowledge: everything that is true he believes to be false, everything that is false he believes to be true. Curiously, these characteristics cause the two brothers to issue identical answers to a given question.

For example, if you ask the honest brother "Is two plus two four?" He will know, because his knowledge is perfectly accurate, that it is. Since he is always honest he will answer "yes."
If you ask the same question to the dishonest brother, he will, because of his inaccurate knowledge, think that the true answer is "no," but because he is a liar, he will also answer "yes."

Now for the riddle: Suppose you met one of these brothers out in a field someplace. Could you, by only asking yes-or-no questions, deduce which brother you were talking to? If so, how many questions would you need to ask and what would they be?
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  #24  
Old Oct 28th 2008, 11:14 AM
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Default Re: Brain Teasers & Riddles

This is actually an easier question than the last in my mind because of the extra qualifiers.

I would ask one question of either brother. The question would be "Is your brother honest?"

If you happened to ask the honest, accurate brother, he would accurately deduce the answer "No" and answer with such. If you happened to ask the lying, inaccurate brother, he would inaccurately deduce the answer to be "No" and answer "Yes". Two different answers and you would easily have knowledge of which brother you were talking to.
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  #25  
Old Oct 28th 2008, 11:45 AM
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Default Re: Brain Teasers & Riddles

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Originally Posted by Greendruid View Post
This is actually an easier question than the last in my mind because of the extra qualifiers.

I would ask one question of either brother. The question would be "Is your brother honest?"

If you happened to ask the honest, accurate brother, he would accurately deduce the answer "No" and answer with such. If you happened to ask the lying, inaccurate brother, he would inaccurately deduce the answer to be "No" and answer "Yes". Two different answers and you would easily have knowledge of which brother you were talking to.
Correct.

You could also ask "Are you the honest, accurate brother?" Or indeed just about any question that included "you" or "your". While both brothers do, in fact, give identical answers when faced with the same question, questions that include the word "you" (or some derivative thereof) are technically different questions for each individual since "you" means a different person in each case. I thought it was an interesting question.

You're up.
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  #26  
Old Oct 28th 2008, 11:56 AM
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Default Re: Brain Teasers & Riddles

Here's a fun one:

Four men were out fishing on a boat in the ocean. A fierce wind blows in the southeast and tips the boat over, completely capsizing it. All four men fall out of the boat and sink to the bottom of the ocean but not a single man got wet! How can this be?
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  #27  
Old Oct 28th 2008, 01:19 PM
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Default Re: Brain Teasers & Riddles

I'll take a shot at this one and guess that all four men were married.
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  #28  
Old Oct 28th 2008, 01:34 PM
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Default Re: Brain Teasers & Riddles

Right you are! Michael is up.
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  #29  
Old Oct 28th 2008, 08:13 PM
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Default Re: Brain Teasers & Riddles

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Right you are! Michael is up.


Here's the next one...

A girl who was just learning to drive went down a one-way street in the wrong direction, but didn't break the law. How come?
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  #30  
Old Oct 28th 2008, 08:31 PM
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Default Re: Brain Teasers & Riddles

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Here's the next one...

A girl who was just learning to drive went down a one-way street in the wrong direction, but didn't break the law. How come?
She was walking?
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