SOLUTION: a chemist has 2 alloys, one of which is 10%gold and 15% lead and the other is 30%gold and 40% lead. how many grams of the 2 alloys should be used to make an alloy that contains 60

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Question 198175: a chemist has 2 alloys, one of which is 10%gold and 15% lead and the other is 30%gold and 40% lead. how many grams of the 2 alloys should be used to make an alloy that contains 60g of gold and 88 g of lead.
This is from a pactive worksheet not a text book
I tried 25X +70%y=148 as one euqation but not sure of the other equation to substitute x for
thanks
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
let x="grams of 10% Au alloy", and y="grams of 30% Au alloy"

(10%)x + (30%)y = 60 ___ multiplying by 3 ___ (30%)x + (90%)y = 180

(15%)x + (40%)y = 88 ___ multiplying by 2 ___ (30%)x + (80%)y = 176

subtracting ___ (10%)y = 4 ___ dividing by 10% ___ y = 40

substituting ___ (10%)x + (30%)(40) = 60 ___ (10%)x + 12 = 60 ___ (10%)x = 48

dividing by 10% ___ x = 480