document.write( "Question 405455: please help me set up this equation : a chemistry student mixes a 10% solution with a 20% solution to get 20L of a 13% solution. how much of each is used?\r
\n" ); document.write( "\n" ); document.write( "i tried to do x + y =20(.13), .1x + .2y = .13
\n" ); document.write( "and y= -2.47, so i don't think i did it right... \r
\n" ); document.write( "\n" ); document.write( "also, i have several more problems like this, so it would be useful to have a generic equation to plug the numbers into...
\n" ); document.write( "
\n" ); document.write( "thanks \n" ); document.write( "
Algebra.Com's Answer #286361 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
A chemistry student mixes a 10% solution with a 20% solution to get 20L of a 13% solution. how much of each is used?
\n" ); document.write( "---------
\n" ); document.write( "Equations
\n" ); document.write( "active + active = active
\n" ); document.write( "0.10x + 0.20(20-x) = 0.13*20
\n" ); document.write( "Multiply thru by 100 to get:
\n" ); document.write( "10x + 20*20 - 20x = 13*20
\n" ); document.write( "-10x = -7*20
\n" ); document.write( "x = (1/2)7
\n" ); document.write( "x = 3.5L (amt of 10% solution needed)
\n" ); document.write( "---
\n" ); document.write( "20-x = 16.5L (amt of 20% solution)
\n" ); document.write( "======================================
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
\n" ); document.write( "=========\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
\n" );