document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=641405>Question 641405</A>: <I><SPAN STYLE=\"word-break: break-all;\"> What quantity of pure acid must be added to 500 mL of a 40% acid solution to produce a 50% acid solution? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #403640 by </B><A HREF=/tutors/aboutme.mpl?userid=ptaylor><B>ptaylor(2198)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ptaylor><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=ptaylor><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=403640\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let x=quantity of pure acid needed<BR>\n" );
document.write( "Now we know that the amount of pure acid that exists before the mixture takes place (x+0.40*500) has to equal the amount of pure acid that exists after the mixture takes place (0.50(500+x)). Soooo<BR>\n" );
document.write( "x+0.40*500=0.50(500+x) simplify<BR>\n" );
document.write( "x+200=250+0.50x  subtract 0.50x and also 200 from each side<BR>\n" );
document.write( "x-0.50x=250-200<BR>\n" );
document.write( "0.50x=50<BR>\n" );
document.write( "x=100 mL quantity of pure acid needed\r<BR>\n" );
document.write( "\n" );
document.write( "CK<BR>\n" );
document.write( "100+200=0.50*600<BR>\n" );
document.write( "300=300<BR>\n" );
document.write( "Hope this helps--ptaylor </SPAN>\n" );
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