document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=786122>Question 786122</A>: <I><SPAN STYLE=\"word-break: break-all;\"> PLEASE HELP ME !!!!<BR>\n" );
document.write( "Pat and Jen volunteer at the library. Pat can shelve a full cart of books 10 minutes faster than Jen. if they work together, they can shelve a full cart in 70 minutes. How long does it take Jen to shelve a full cart by herself (give an exact answer and an answer rounded to the nearest minute)?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #477821 by </B><A HREF=/tutors/aboutme.mpl?userid=xinxin><B>xinxin(76)</B></A><img src=\"/images/stars/stars-08.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=xinxin><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=477821\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The problem is tricky because you may mistakenly add their individual working time to the total of 70 minutes.<BR>\n" );
document.write( "Suppose Jen needs X minutes to shelve a full cart by herself, and the number of books on the cart is A, then:<BR>\n" );
document.write( "(A/(X-10) + A/X ) * 70 = A<BR>\n" );
document.write( "X^2 -150X +700 =0<BR>\n" );
document.write( "Solve for X, get X = 145 or X = 5. Well if X is 5 then Pat will have a negative working time. Thus Jen uses 145 minutes to shelve a full cart. </SPAN>\n" );
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