SOLUTION: Anne and Nancy use a metal alloy that is 24.9% copper to make jewelry. How many ounces of a 20% alloy must be mixed with a 27% alloy to form 100 ounces of the desired alloy?

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Anne and Nancy use a metal alloy that is 24.9% copper to make jewelry. How many ounces of a 20% alloy must be mixed with a 27% alloy to form 100 ounces of the desired alloy?       Log On


   

Question 112780: Anne and Nancy use a metal alloy that is 24.9% copper to make jewelry. How many ounces of a 20% alloy must be mixed with a 27% alloy to form 100 ounces of the desired alloy?
Answer by SHUgrad05(58) About Me  (Show Source):
You can put this solution on YOUR website!
Let x= 20% alloy; y= 27% alloy
Set up system of equations:
.20x+.27y=24.9
x+y=100 -->multiply by -.20
.20x+.27y=24.9
-.20x+-.20y=-20.00
.07y=4.9
y=70 -->plug back into one of the original equations
x+70=100
x=30
30 ounces of 20% alloy; 70 ounces of 27% alloy