SOLUTION: how much does an alloy that is 20% copper should be mixed with 200 onces of an alloy that is 90% copper in order to get an alloy that is 30% copper

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Question 236564: how much does an alloy that is 20% copper should be mixed with 200 onces of an alloy that is 90% copper in order to get an alloy that is 30% copper
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
how much does an alloy that is 20% copper should be mixed with 200 onces of an alloy that is 90% copper in order to get an alloy that is 30% copper
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Equation:
copper + copper = copper
0.20x + 0.90*200 = 0.30(x+200)
Multiply thru by 100 to get:
20x + 90*200 = 30x + 30*200
-10x = -60*200
x = 1200 onces (amt of 20% alloy needed in the mixture)
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Cheers,
Stan H.