Question 214314
Brass is an alloy made up of copper and zinc in varying proportions. How much brass containing 75.5% copper must be combined with a different brass containing 86.3% copper to make 5250kg of brass containing 80.0% copper 
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Equation:
copper + copper = copper
0.755x + 0.863(5250-x) = 0.80*5250
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Multiply thru by 1000 to get:
755x + 863*5250 - 863x = 800*5250
-108x = -63*5250
x = 3062.5 kg (amt. of 75.5% copper in the mixture)
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5250-3062.5 = 2187.5 kg (amt of 86.3% copper in the mixture)
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Cheers,
Stan H.