document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1129074>Question 1129074</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A motorist travels travels 400 km partly at 100 km/hr and partly at 80 km/h. If he had traveled at 80 kn/hr instead of 100 km/hr and had 100 km/h instead of 80 km/hr, the journey would have taken 0.5 h longer. find his time for the trip.  </SPAN>\n" );
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document.write( "Let the distances (km) for the two parts of the trip be x and 400-x.  Then<br><BR>\n" );
document.write( "The total number of hours for the trip, at 100km/hr for the first part and 80km/hr for the second, was<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%2F100%2B%28400-x%29%2F80 ALIGN=MIDDLE  ALT=\"x%2F100%2B%28400-x%29%2F80\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "If the two speeds had been switched, the total number of hours would have been<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%2F80%2B%28400-x%29%2F100 ALIGN=MIDDLE  ALT=\"x%2F80%2B%28400-x%29%2F100\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "The second trip would have taken 0.5 hours longer:<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%2F80%2B%28400-x%29%2F100+=+x%2F100%2B%28400-x%29%2F80%2B0.5 ALIGN=MIDDLE  ALT=\"x%2F80%2B%28400-x%29%2F100+=+x%2F100%2B%28400-x%29%2F80%2B0.5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "Multiply through by the LCM, 400:<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5x%2B4%28400-x%29+=+4x%2B5%28400-x%29%2B200 ALIGN=MIDDLE  ALT=\"5x%2B4%28400-x%29+=+4x%2B5%28400-x%29%2B200\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "Solve....<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5x%2B1600-4x+=+4x%2B2000-5x%2B200 ALIGN=MIDDLE  ALT=\"5x%2B1600-4x+=+4x%2B2000-5x%2B200\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2x+=+600 ALIGN=MIDDLE  ALT=\"2x+=+600\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+300 ALIGN=MIDDLE  ALT=\"x+=+300\"   DISABLED_style= \"max-width:90%; height:auto;\" ><br><BR>\n" );
document.write( "He traveled at 100km/hr for 300 km (3 hours) and at 80 km/hr for 100 km (1.25 hours); total time 4.25 hours.<br><BR>\n" );
document.write( "If the speeds had been switched, he would have traveled at 80km/hr for 300 km (3.75 hours) and 100km at 100km/hr (1 hour); total time 4.75 hours. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );