- #1

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There is a mint, lets say the Denver mint. In the mint there are 100 penny making machines. In the problems below there is something wrong with one of the machines. You may produce as many coins as you would like from any of the machines and weigh them, but there is only one scale. The goal is to find the broken machine with the lest number of weigh ins. Oh and you will break the scale if you put infinite coins on it.

#1

1 of the hundred machines produces coins that weigh 10% more then they should.

How many weigh ins do you have to have to find the broken machine? What is your method?

#2

1 of the hundred machines produces coins that weigh 10% or 5%(not both, all the coins produced from this machine are 10% heavier or 5% heavier) more then they should.

How many weigh ins do you have to have to find the broken machine? What is your method?

#3

1 of the hundred machines produces coins that weighs plus or minus 10%(That is any given coin is +10% or minus 10%) more then they should.

How many weigh ins do you have to have to find the broken machine? What is your method?

Some of you have more then likely seen #1 and #2, but #3 is my own little twist.