# Box of Coins

Discussion in 'Basic Math' started by nycmathguy, Jan 26, 2022.

1. ### nycmathguy

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nycmathguy, Jan 26, 2022

2. ### MathLover1

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She does know that genuine coins weigh 1 oz, but forgeries weigh 2oz. => difference is 1 oz
It is known that there is only one bag with forgeries. To identify that bag, Ishita can follow a simple procedure.
She should take out 1 coin from the 1st bag,
2 coins from the 2nd bag,
3 coins from the 3rd bag and
similarly 10 coins from the 10th bag.

Now she should simply weigh all these picked coins together.
If there were no forgeries, then the total weight should be (1+2+3+ . . . +10) = 55oz.

Now, if the total weight comes out to be greater than 56 oz then she can conclude that the one bag contain forgeries.

so, she just need to pay good attention when the weight will change

MathLover1, Jan 31, 2022
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3. ### nycmathguy

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I like the way you reason your way to a conclusion.
By the way, my root tip extraction was changed from the 17th to this Wednesday. So, on 2/2/22, I will undergo oral surgery which involves a slight incision in the gum area.

I am a bit nervous about the procedure but it must be done. I picked 30 antibiotics today for less than \$7. Once the infection is gone, the pain is gone. I took my first pill this evening at 6:07pm. The next pill must be taken 8 hours later at 2:07am.

nycmathguy, Feb 1, 2022
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4. ### EmptySetBlues

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No, she does not need to pay attention to when the weight changes. 55 real (2 oz) coins will weigh 110 oz. 55 coins picked by the above procedure will be short by N ounces, where N is the number of forgeries. A shortage of N oz. comes from box N.

EmptySetBlues, Apr 6, 2022
5. ### nycmathguy

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I believe my reply was meant for another member. So, why step into this conversation? Member MathLover1 is not only a math helper; she is also my friend. My reply to her does not concern you.

nycmathguy, Apr 6, 2022
6. ### EmptySetBlues

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You are correct. My mistake, and my apologies.

EmptySetBlues, Apr 6, 2022
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