document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1103607>Question 1103607</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A man can do a certain task in 21 hours, another man can do the task in 28 hours and a boy can do the task in 48 hours. Find how long it will take to do the task if all three work. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #718291 by </B><A HREF=/tutors/aboutme.mpl?userid=richwmiller><B>richwmiller(17219)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=richwmiller><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=richwmiller><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=718291\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a=21 b=28 c=48<BR>\n" );
document.write( "1/a+1/b+1/c=1/x<BR>\n" );
document.write( "1/21+1/28+1/48=1/x<BR>\n" );
document.write( "1344/28224+1008/28224+588/28224=1/x<BR>\n" );
document.write( "2940/28224=1/x<BR>\n" );
document.write( "28224/2940=x<BR>\n" );
document.write( "or 9.6 hours working together<BR>\n" );
document.write( "check<BR>\n" );
document.write( "1/a+1/b+1/c=1/x<BR>\n" );
document.write( "1/21+1/28+1/48=1/9.6<BR>\n" );
document.write( "1344/28224+1008/28224+588/28224=1/9.6<BR>\n" );
document.write( "2940/28224=1/9.6<BR>\n" );
document.write( "28224/2940=9.6<BR>\n" );
document.write( "9.6=9.6<BR>\n" );
document.write( "ok<BR>\n" );
document.write( "codewt3w<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );