document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1058316>Question 1058316</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A small heating unit takes 56 h longer to melt a piece of iron than does a larger unit. Working together, the heating units can melt the iron in 21 h. How long would it take each heating unit, working alone, to melt the iron? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #673362 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><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=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=673362\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Rate of heating for large unit alone:<BR>\n" );
document.write( "[ 1 piece of iron melted ] / [ t hrs ]<BR>\n" );
document.write( "Rate of heating for small unit alone:<BR>\n" );
document.write( "[ 1 piece of iron melted ] / [ t + 56 hrs ]<BR>\n" );
document.write( "Rate for both units together:<BR>\n" );
document.write( "[ 1 piece of iron melted ] / [ 21 hrs ]<BR>\n" );
document.write( "--------------------------------------<BR>\n" );
document.write( "Add the different units rates of melting<BR>\n" );
document.write( "to get rate working together:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1%2Ft+%2B+1%2F%28+t%2B56+%29+=+1%2F21+ ALIGN=MIDDLE  ALT=\"+1%2Ft+%2B+1%2F%28+t%2B56+%29+=+1%2F21+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiply both sides by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t%2A%28+t%2B56+%29%2A21+ ALIGN=MIDDLE  ALT=\"+t%2A%28+t%2B56+%29%2A21+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+21%2A%28+t%2B56+%29+%2B+21t+=+t%2A%28+t%2B56+%29+ ALIGN=MIDDLE  ALT=\"+21%2A%28+t%2B56+%29+%2B+21t+=+t%2A%28+t%2B56+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+21t+%2B+1176+%2B+21t+=+t%5E2+%2B+56t+ ALIGN=MIDDLE  ALT=\"+21t+%2B+1176+%2B+21t+=+t%5E2+%2B+56t+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t%5E2+%2B+14t+-+1176+=+0+ ALIGN=MIDDLE  ALT=\"+t%5E2+%2B+14t+-+1176+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "I'll complete square:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t%5E2+%2B+14t+%2B+%2814%2F2%29%5E2+=+1176+%2B+%2814%2F2%29%5E2+ ALIGN=MIDDLE  ALT=\"+t%5E2+%2B+14t+%2B+%2814%2F2%29%5E2+=+1176+%2B+%2814%2F2%29%5E2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t%5E2+%2B+14t+%2B+49+=+1176+%2B+49+ ALIGN=MIDDLE  ALT=\"+t%5E2+%2B+14t+%2B+49+=+1176+%2B+49+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28+t+%2B+7+%29%5E2+=+1225+ ALIGN=MIDDLE  ALT=\"+%28+t+%2B+7+%29%5E2+=+1225+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28+t+%2B+7+%29%5E2+=+35%5E2+ ALIGN=MIDDLE  ALT=\"+%28+t+%2B+7+%29%5E2+=+35%5E2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+%2B+7+=+35+ ALIGN=MIDDLE  ALT=\"+t+%2B+7+=+35+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+28+ ALIGN=MIDDLE  ALT=\"+t+=+28+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "and<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+%2B+56+=+84+ ALIGN=MIDDLE  ALT=\"+t+%2B+56+=+84+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "------------------<BR>\n" );
document.write( "The smaller unit alone takes 84 hrs<BR>\n" );
document.write( "The larger unit alone takes 28 hrs<BR>\n" );
document.write( "---------------------------------<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1%2Ft+%2B+1%2F%28+t%2B56+%29+=+1%2F21+ ALIGN=MIDDLE  ALT=\"+1%2Ft+%2B+1%2F%28+t%2B56+%29+=+1%2F21+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1%2F28+%2B+1%2F84+=+1%2F21+ ALIGN=MIDDLE  ALT=\"+1%2F28+%2B+1%2F84+=+1%2F21+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+.035714+%2B+.011905+=+.047619+ ALIGN=MIDDLE  ALT=\"+.035714+%2B+.011905+=+.047619+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+.047619+=+.047619+ ALIGN=MIDDLE  ALT=\"+.047619+=+.047619+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );