document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1197605>Question 1197605</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A computer technician travels 220 on a service call. He averaged 40 miles per hour for<BR>\n" );
document.write( "part of the trip and averaged 50 mph for the rest of the trip. If the total trip took five hours<BR>\n" );
document.write( "how long did he travel at a rate of 40 miles per hour? </SPAN>\n" );
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document.write( "First a standard algebraic method for solving the problem....<br><BR>\n" );
document.write( "x = hours at 40mph<BR>\n" );
document.write( "5-x = hours at 50mph<br><BR>\n" );
document.write( "40(x) = distance traveled at 40mph<BR>\n" );
document.write( "50(5-x) = distance traveled at 50mph<br><BR>\n" );
document.write( "The total distance was 220 miles:<br><BR>\n" );
document.write( "40x+50(5-x) = 220<BR>\n" );
document.write( "40x+250-50x = 220<BR>\n" );
document.write( "30 = 10x<BR>\n" );
document.write( "x = 3<br><BR>\n" );
document.write( "ANSWER: He traveled for 3 hours at 40mph (and 2 hours at 50mph)<br><BR>\n" );
document.write( "CHECK: 3(40)+2(50) = 120+100 = 220<br><BR>\n" );
document.write( "And next an alternative method that I like to use on problems like this; look at it and see if it \"works\" for you.<br><BR>\n" );
document.write( "(1) The average speed was 220/5 = 44mph<BR>\n" );
document.write( "(2) the average of 44mph is 4/10 = 2/5 of the way from 40mph to 50mph (use a number line to see that, if it helps)<BR>\n" );
document.write( "(3) that means 2/5 of the total time was spent at the higher rate<br><BR>\n" );
document.write( "ANSWER: 2/5 of 5 hours, or 2 hours, at 50mph; the other 3 hours at 40mph<br><BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );