document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=581415>Question 581415</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Okay I'm stumped on this problem. I have tried to figure out the equation but I keep geting stuck. The problem is: \"A chemist has a 90% solution of sulfuric acid and a 70% solution of the same acid. How many gallons of each must be mixed in order to make 200 gallons of 75% solution?\"<BR>\n" );
document.write( "Here's what I know: I know that x is the amount of the 90% solution and that y would be the amount of the 70% solution. I think that the equation would be .90x + .70y = .75 and that the other equation is x+y=200. but I am not sure I did that right and I keep getting fractions as my answer. Help please. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #371664 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=371664\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Okay I'm stumped on this problem. I have tried to figure out the equation but I keep geting stuck. The problem is: \"A chemist has a 90% solution of sulfuric acid and a 70% solution of the same acid. How many gallons of each must be mixed in order to make 200 gallons of 75% solution?\"<BR>\n" );
document.write( "Here's what I know: I know that x is the amount of the 90% solution and that y would be the amount of the 70% solution. I think that the equation would be .90x + .70y = .75 and that the other equation is x+y=200. but I am not sure I did that right and I keep getting fractions as my answer. Help please.<BR>\n" );
document.write( ".<BR>\n" );
document.write( "You almost had it right.  It should have been:<BR>\n" );
document.write( "Let x = amount (gallons) of 90% solution<BR>\n" );
document.write( "and y = amount (gallons) of 70% solution<BR>\n" );
document.write( ".<BR>\n" );
document.write( "x+y=200 (equation 1)<BR>\n" );
document.write( ".90x + .70y = .75(200)   (equation 2)<BR>\n" );
document.write( ".<BR>\n" );
document.write( "Solving equation 1 for y<BR>\n" );
document.write( "x+y=200<BR>\n" );
document.write( "y=200-x<BR>\n" );
document.write( "Substitute above into equation 2:<BR>\n" );
document.write( ".90x + .70y = .75(200)<BR>\n" );
document.write( ".90x + .70(200-x) = .75(200)<BR>\n" );
document.write( ".90x + 140-.70x = 150<BR>\n" );
document.write( ".20x + 140 = 150<BR>\n" );
document.write( ".20x = 10<BR>\n" );
document.write( "x = 50 gallons (of 90% solution)<BR>\n" );
document.write( ".<BR>\n" );
document.write( "70% solution:<BR>\n" );
document.write( "x+y=200<BR>\n" );
document.write( "50+y=200<BR>\n" );
document.write( "y = 150 gallons\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );