document.write( "Question 57509: Melly makes a new alloy out of copper (density of 8.9g/cubic cm)and aluminum (density of 2.6g/cubic centimeter). She puts in 10 more grams of copper than aluminum. The fnal alloy has a density of 7g/cubic cm. How much copper did she put in the alloy? \n" ); document.write( "
Algebra.Com's Answer #39401 by ankor@dixie-net.com(22740)\"\" \"About 
You can put this solution on YOUR website!
Melly makes a new alloy out of copper (density of 8.9g/cubic cm)and aluminum (density of 2.6g/cubic centimeter). She puts in 10 more grams of copper than aluminum. The final alloy has a density of 7g/cubic cm. How much copper did she put in the alloy?
\n" ); document.write( ":
\n" ); document.write( "Not really sure about this, will treat it like a normal mixture problem
\n" ); document.write( ":
\n" ); document.write( "Let x = amt of copper: (x-10) = amt of aluminum
\n" ); document.write( "Total amt of them added together = (2x-10)
\n" ); document.write( ":
\n" ); document.write( "8.9x + 2.6(x-10) = 7(2x-10)
\n" ); document.write( "8.9x + 2.6x - 26 = 14x - 170
\n" ); document.write( "8.9x + 2.6x - 14x = -170 + 26
\n" ); document.write( "-2.5x = -44
\n" ); document.write( "x = -44/-2.5
\n" ); document.write( "x = +17.6 grams of copper
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check:
\n" ); document.write( "7.6 grams of aluminum, Total: 17.6 + 7.6 = 25.2 grams
\n" ); document.write( "8.9(17.6) + 2.6(7.6) = 7(25.2)
\n" ); document.write( "156.64 + 19.76 = 176.4\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
\n" );