document.write( "Question 1025203: A metal alloy is 25% copper. Another metal alloy is 50% copper. How many grams of the 50% copper alloy should be used to make 1000 grams of a metal alloy that is 45% copper ? \n" ); document.write( "
Algebra.Com's Answer #640484 by mathmate(429)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "Question:
\n" ); document.write( "A metal alloy is 25% copper. Another metal alloy is 50% copper. How many grams of the 50% copper alloy should be used to make 1000 grams of a metal alloy that is 45% copper ?
\n" ); document.write( "
\n" ); document.write( "Solution:
\n" ); document.write( "The key to answering mixture problems is to calculate the weight of the pure components.
\n" ); document.write( "We know the total is 1000 grams, and 50% means 450 grams of pure copper.
\n" ); document.write( "Let x=weight of the 50% alloy, then
\n" ); document.write( "(1000-x)=weight of the 25% alloy.
\n" ); document.write( "Total weight of pure copper
\n" ); document.write( "=x(0.50)+(1000-x)(0.25) g
\n" ); document.write( "Since we know this weight must be 500 grams, so we equate and solve for x.
\n" ); document.write( "x(0.50)+(1000-x)(0.25) = 500
\n" ); document.write( "0.5x-0.25x+250=450
\n" ); document.write( "0.25x=450-250=200
\n" ); document.write( "means
\n" ); document.write( "x=200/0.25=800
\n" ); document.write( "Answer: 800 grams of the 50% copper alloy will be needed
\n" ); document.write( "(hence (1000-800)=200 grams of the 25% alloy. \n" ); document.write( "
\n" );