document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1082568>Question 1082568</A>: <I><SPAN STYLE=\"word-break: break-all;\"> 5 kg of heavy water of unknown isotopic purity, when added to 10 kg of heavy water of different grade produced a mixture of isotopic purity of 80% by weight. when 2 kg of the first sample is added to 3 kg of the second sample, the resulting mixture had an isotopic purity of 78% by weight. calculate the isotopic purities of the two samples. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #696623 by </B><A HREF=/tutors/aboutme.mpl?userid=addingup><B>addingup(3677)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=addingup><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=addingup><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=696623\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 5x + 10y = 12 (15(0.8)) multiply both sides times 2<BR>\n" );
document.write( "2x + 3x = 3.9 (5(0.78)) multiply both sides times -5 and add to the other equation<BR>\n" );
document.write( "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<BR>\n" );
document.write( "10x + 20y = 24<BR>\n" );
document.write( "-10x + -15y = -19.5<BR>\n" );
document.write( "-------------------<BR>\n" );
document.write( "0x + 5y = 4.5<BR>\n" );
document.write( "5y = 4.5<BR>\n" );
document.write( "y = 0.9 = 90%<BR>\n" );
document.write( "plug this into one of the original equations to solve for x.<BR>\n" );
document.write( "5x + 10(0.9) = 12<BR>\n" );
document.write( "= 0.6 <BR>\n" );
document.write( "try the other equation if you want to double-check:<BR>\n" );
document.write( "2x + 3(0.9) = 3.9<BR>\n" );
document.write( "= 0.6 </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );