document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=342950>Question 342950</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me solve this problem: Mr.Tan makes monthly visits to his parents in Baguio, a distance of 240km from Manila. He found out that if he increases the average speed by 10km per hour, he could save a total of20 minutes for the journey. Find the speed at which Mr.Tan originally traveled. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #245604 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=245604\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Mr.Tan makes monthly visits to his parents in Baguio, a distance of 240km from Manila.<BR>\n" );
document.write( " He found out that if he increases the average speed by 10km per hour, he could<BR>\n" );
document.write( " save a total of 20 minutes for the journey. <BR>\n" );
document.write( "Find the speed at which Mr.Tan originally traveled.<BR>\n" );
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document.write( "Let s = his original speed<BR>\n" );
document.write( "then<BR>\n" );
document.write( "(s+10) = his faster speed<BR>\n" );
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document.write( "Change 20 min to <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F3 ALIGN=MIDDLE  ALT=\"1%2F3\"   DISABLED_style= \"max-width:90%; height:auto;\" > hr<BR>\n" );
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document.write( "Write a time equation, time = dist/speed<BR>\n" );
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document.write( "slow speed time - fast speed time = 1/3 hr<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=240%2Fs ALIGN=MIDDLE  ALT=\"240%2Fs\"   DISABLED_style= \"max-width:90%; height:auto;\" > - <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=240%2F%28%28s%2B10%29%29 ALIGN=MIDDLE  ALT=\"240%2F%28%28s%2B10%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F3 ALIGN=MIDDLE  ALT=\"1%2F3\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "Multiply equation by 3s(s+10) to eliminate the denominators, results:<BR>\n" );
document.write( "3(s+10)*240 - 3s(240) = s(s+10)<BR>\n" );
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document.write( "240(3s+30) - 720s = s^2 + 10s<BR>\n" );
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document.write( "720s + 7200 - 720s = s^2 + 10x<BR>\n" );
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document.write( "A quadratic equation<BR>\n" );
document.write( "s^2 + 10s - 7200 = 0<BR>\n" );
document.write( "factors to<BR>\n" );
document.write( "(s+90)(s-80) = 0<BR>\n" );
document.write( "the positive solution;<BR>\n" );
document.write( "s = 80 km/h is his original speed<BR>\n" );
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document.write( "Check our solution<BR>\n" );
document.write( "Find the actual time of each (90 km/hr is the faster speed)<BR>\n" );
document.write( "240/80 = 3 hrs<BR>\n" );
document.write( "240/90 = 2.67 hrs<BR>\n" );
document.write( "--------------------<BR>\n" );
document.write( "differs: .33 hr which ~ 20 min  </SPAN>\n" );
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