document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=557241>Question 557241</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Tina hiked 15 km up a mountain trail.  Her return trip along the same trail took 1/2 hour less, because she increased her speed by 1 km/hr.  How long did it take her to climb up and down the trail? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #362553 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=362553\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Tina hiked 15 km up a mountain trail. <BR>\n" );
document.write( "Her return trip along the same trail took 1/2 hour less, because she increased her speed by 1 km/hr. <BR>\n" );
document.write( "How long did it take her to climb up and down the trail?<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Let t = time down the trail<BR>\n" );
document.write( "then<BR>\n" );
document.write( "(t+.5) = up the trail<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Write a speed equation: Speed = dist/time<BR>\n" );
document.write( ":<BR>\n" );
document.write( "speed down - speed up = 1 km/h<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=15%2Ft ALIGN=MIDDLE  ALT=\"15%2Ft\"   DISABLED_style= \"max-width:90%; height:auto;\" > - <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=15%2F%28%28t%2B.5%29%29 ALIGN=MIDDLE  ALT=\"15%2F%28%28t%2B.5%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 1<BR>\n" );
document.write( "Multiply eq by t(t+.5), results:<BR>\n" );
document.write( "15(t+.5) - 15t = t(t+.5)<BR>\n" );
document.write( "15t + 7.5 - 15t = t^2 + .5t<BR>\n" );
document.write( "A quadratic equation from this<BR>\n" );
document.write( "0 = t^2 + .5t - 7.5<BR>\n" );
document.write( "You can use the quadratic formula but this will factor<BR>\n" );
document.write( "(t-2.5)(t+3) = 0<BR>\n" );
document.write( ":<BR>\n" );
document.write( "t = 2.5 hrs; is the time down the hill<BR>\n" );
document.write( "then<BR>\n" );
document.write( "2.5 + .5 = 3 hr; is the time up the hill<BR>\n" );
document.write( ";<BR>\n" );
document.write( "Check this by finding the speeds:<BR>\n" );
document.write( "15/2.5 = 6 km/h down the hill<BR>\n" );
document.write( "15/3 = 5 km/h up the hill\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );