Official Trivia/Riddles/Lateral Thinking Thread

You take 1 coin from the first bag, 2 from the second, 3 from the third, etc... and weigh them. Since only 1 bag has fake coins, 9 bags are real, meaning 90 grams are real. Subtract 90 from your total weight, and divide by 20, and the number you get is the amount of coins you got from x bag, meaning its the fake one.

You take 1 coin from the first bag, 2 from the second, 3 from the third, etc... and weigh them. Since only 1 bag has fake coins, 9 bags are real, meaning 900 grams are real. Subtract 900 from your total weight, and divide by 200, and the number you get is the amount of coins you got from x bag, meaning its the fake one.


wth?

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Originally Posted by Calliander

I see where you're going with this, but here:

1 coin from first bag: 10 grams
2 coins from second bag: 20 grams
and so on

I think you're assuming they're 1 gram each. The real ones are 10 grams and the fake ones are 20 grams. You're close.

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So then, take 10 from the first one... 20 from the second...? Shoot... I don't even know if the bag has that many coins. :confused:

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Originally Posted by red_war_machine

I mean, just by holding them.

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What if you're holding the heavier one in your strong arm? You'd have to lift both with your strong arm, a.k.a. two weighings.

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Originally Posted by Calliander

Nope, one weighing. I have the riddle and solution in front of me.

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Okay... take one from the first bag, two from the second and so on.

Now, if they were all real, you'd have 550grams. Take 550 grams away from what you DO have and divide by 20. Then, it's that bag.

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Originally Posted by MVS

You take 1 coin from the first bag, 2 from the second, 3 from the third, etc... and weigh them. Since only 1 bag has fake coins, 9 bags are real, meaning 90 grams are real. Subtract 90 from your total weight, and divide by 20, and the number you get is the amount of coins you got from x bag, meaning its the fake one.

You take 1 coin from the first bag, 2 from the second, 3 from the third, etc... and weigh them. Since only 1 bag has fake coins, 9 bags are real, meaning 900 grams are real. Subtract 900 from your total weight, and divide by 200, and the number you get is the amount of coins you got from x bag, meaning its the fake one.


wth?

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I didn't notice that it was taken from me word for word except for an extra digit in the numbers... but maybe he's on to something...

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Originally Posted by MVS

You take 1 coin from the first bag, 2 from the second, 3 from the third, etc... and weigh them. Since only 1 bag has fake coins, 9 bags are real, meaning 90 grams are real. Subtract 90 from your total weight, and divide by 20, and the number you get is the amount of coins you got from x bag, meaning its the fake one.

You take 1 coin from the first bag, 2 from the second, 3 from the third, etc... and weigh them. Since only 1 bag has fake coins, 9 bags are real, meaning 900 grams are real. Subtract 900 from your total weight, and divide by 200, and the number you get is the amount of coins you got from x bag, meaning its the fake one.


wth?

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That's why I deleted it. Seemed like a good idea at the time, when you look at his answer and the reply he got. :P

I think C means that your math is off, but your idea is correct.

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Originally Posted by red_war_machine

That's why I deleted it. Seemed like a good idea at the time, when you look at his answer and the reply he got. :P

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!

Sly bastard.

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Originally Posted by red_war_machine

Okay... take one from the first bag, two from the second and so on.

Now, if they were all real, you'd have 550grams. Take 550 grams away from what you DO have and divide by 20. Then, it's that bag.

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My math was screwed up, you got it...

nt though, SMX.

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Originally Posted by SearchManX

So then, take 10 from the first one... 20 from the second...? Shoot... I don't even know if the bag has that many coins. :confused:

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What I was trying to say is that you were saying that the total of all the coins you removed was 90, which would be if you took one from only nine of the bags.