document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1076470>Question 1076470</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Twin brothers, Andy and Brian, can mow their grandparent's lawn together in 72 minutes. Billy could mow the lawn by himself in 17 more minutes than it would take Andy. How long would it take each person to mow the lawn alone? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #691080 by </B><A HREF=/tutors/aboutme.mpl?userid=jorel1380><B>jorel1380(3719)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jorel1380><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=jorel1380><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=691080\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let a be for Andy, and b be for Brian. Then:<BR>\n" );
document.write( "1/a + 1/b=1/72<BR>\n" );
document.write( "Brian takes 17 more minutes than Andy, working alone so b=a+17. Then:<BR>\n" );
document.write( "1/a + 1/a+17=1/72<BR>\n" );
document.write( "72/a + 72/a+17=1<BR>\n" );
document.write( "72(a+17)+72a=aČ+17a<BR>\n" );
document.write( "aČ-127a-1224=0<BR>\n" );
document.write( "(a+9)(a-136)=0<BR>\n" );
document.write( "a=-9 or 136<BR>\n" );
document.write( "Using the positive value, we get Andy's time working alone as 136 minutes, and Brians' time as 153 minutes. &#9786;&#9786;&#9786;&#9786;<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );