document.write( "Question 170452This question is from textbook Introductory Algebra
\n" ); document.write( ": Solve the problem. 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? \n" ); document.write( "
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Solve the problem. 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?
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\n" ); document.write( "They want to make 100 oz that's 24.9% Cu. That 100 oz will contain 24.9 oz of Cu.
\n" ); document.write( "They have 20% and 27% available.
\n" ); document.write( "If they use x oz of the 20%, then they'll need 100-x ounces of the 27%.
\n" ); document.write( "The copper in x ounces of 20% is x/5.
\n" ); document.write( "The remaining will have 0.27*(100-x) ounces of copper in it.
\n" ); document.write( "So,
\n" ); document.write( "0.2x + 0.27*(100-x) = 24.9
\n" ); document.write( "0.2x + 27 - 0.27x = 24.9
\n" ); document.write( "-0.07x = -2.1
\n" ); document.write( "x = 30 ounces (of the 20%)
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