I bet you cant figure this one out

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SUMMARY

The discussion revolves around a classic logic puzzle involving 12 pennies, where one penny is either heavier or lighter than the others. The challenge is to identify the odd penny using a balance scale in only three weighings. A suggested solution involves dividing the pennies into groups of six, weighing them to determine the heavier group, and then further narrowing down to three pennies for the final weighing. This method effectively utilizes a binary search approach to solve the problem efficiently.

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  • Ability to perform systematic grouping and elimination
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  • Research advanced problem-solving strategies in logic puzzles
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I bet you can't figure this one out!

Ive been working on this problem for extra credit in one of my classes all morning and its driving me nuts. The problem is "you are given 12 pennies, they all weight exactly the same except one, your a given a balance scale and need to figure out if the penny that is different is lighter or heavier than the rest, and you can only use the scale three times" I hope someone can help me out on this one.

Thanks
 
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Hi schwic,
I don't why you have posted this old puzzle in the physics section. Just search the Brain Teasers forum, and you're bound to come across many threads about the same or a similar puzzle.
 
schwic said:
Ive been working on this problem for extra credit in one of my classes all morning and its driving me nuts. The problem is "you are given 12 pennies, they all weight exactly the same except one, your a given a balance scale and need to figure out if the penny that is different is lighter or heavier than the rest, and you can only use the scale three times" I hope someone can help me out on this one.

Thanks
Do a binary search on the pennies. Divide them into 6 and 6 and take the heavier 6. Split those up and take the heavier 3. I will leave you to determine how you do the last weigh.

AM
 

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