SOLUTION: Anne and Nancy use a metal alloy that is 19.75% copper to make jewalry. How many ounces of an 18% alloy must be mixed with a 21% alloy to form 108 ounces of the desired alloy?
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-> SOLUTION: Anne and Nancy use a metal alloy that is 19.75% copper to make jewalry. How many ounces of an 18% alloy must be mixed with a 21% alloy to form 108 ounces of the desired alloy?
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Question 146437: Anne and Nancy use a metal alloy that is 19.75% copper to make jewalry. How many ounces of an 18% alloy must be mixed with a 21% alloy to form 108 ounces of the desired alloy? Answer by nerdybill(7384) (Show Source):
You can put this solution on YOUR website! Anne and Nancy use a metal alloy that is 19.75% copper to make jewalry. How many ounces of an 18% alloy must be mixed with a 21% alloy to form 108 ounces of the desired alloy?
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Let x = ounces of 18% copper
and y = ounces of 21% copper
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since we have two unknowns, we need two equations.
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from:"use a metal alloy that is 19.75% copper" we get equation 1:
.18x + .21y = 19.75
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from:"form 108 ounces of desired alloy" we get equation 2:
x + y = 108
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Solve equation 2 for x we get:
x + y = 108
x = 108 - y
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Substitute this into equation 1 and solve for y:
.18x + .21y = 19.75
.18(108 - y) + .21y = 19.75
.18(108 - y) + .21y = 19.75
19.44 - .18y + .21y = 19.75
19.44 + .03y = 19.75
.03y = .31
y = 10.3333 (10 and 1/3) ounces
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substitute the above into equation 2 and solve for x:
x + y = 108
x + 10.333 = 108
x = 108 - 10.333
x = 97.667 (97 and 2/3) ounces
