document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=142784>Question 142784</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/0534386172/algebrahomeworkh></A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> Mark can overhaul an engine in 20 hours and Phil can do the same job by himself in 30 hours.   If they both work together for a time and then Mark finishes the job by himslef in 5 hours.  How long did they work together? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #103891 by </B><A HREF=/tutors/aboutme.mpl?userid=scott8148><B>scott8148(6628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=scott8148><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=scott8148><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=103891\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Mark does 1/4 (5/20) of the job alone, so together he and Phil do 3/4\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "let x= time together\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "x/20+x/30=3/4 __ multiplying by 60 (LCD) __ 3x+2x=45 __ 5x=45 __ x=9 </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );