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put this solution on YOUR website! A contractor mixes concrete from bags of pre-mix for small jobs. How many bags with 6% cement should he mix with 5 bags of 14% cement to produce a mix containing 10% cement?
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Let x = bags of 6% cement
then
"cement from 6%" + "cement from 14%" = "total amount of cement"
.06x + .14(5) = .10(x+5)
.06x + .7 = .10x + .5
.7 = .04x + .5
.2 = .04x
5 bags = x