Posted by chad on .
assume that a jeweler needs 80 grams of an alloy that is 30% gold. He has avaliable one alloy that is 5% gold and another that is 85% gold; he will mix some of each If x equal the number of grams of the first alloy (so the number of grams of the second is 80x), find x

algebra 
Reiny,
solve
.05x + .85(80x) = .3(80)