Question 654333
how much of an alloy that is 30% copper should be mixed with 100 ounces of an alloy that is 80% copper in order to get an alloy that is 40% copper?
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let x=amt of 30% copper to be mixed
x+100=amt of 40% copper alloy
..
30%x+80%*100=40%(x+100)
.3x+80=.4x+40
.x=40
x=400
amt of 30% copper to be mixed=400 ounces