document.write( "Question 1059912: If a bicyclist is traveling 41 miles at a certain speed, the return speed is made 6 mph slower. The total time for the round trip is 15 hours. What is the average speed of the bicyclist on the first trip?
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Algebra.Com's Answer #674961 by Boreal(15235) You can put this solution on YOUR website! x=speed \n" ); document.write( "x*t=distance \n" ); document.write( "x*t=41, so the outbound time is 41/x \n" ); document.write( "(x-6)*t=41 \n" ); document.write( "t=41/(x-6), which is the inbound time. \n" ); document.write( "Both times add to 15 \n" ); document.write( "41/x+{41/(x-6)}=15 \n" ); document.write( "Clear fractions by multiplying everything by x(x-6) \n" ); document.write( "41(x-6)+41x=15x(x-6) \n" ); document.write( "41x-246+41x=15x^2-90x \n" ); document.write( "15x^2-172x+246=0 \n" ); document.write( "x=(1/30)(172+/-sqrt (172^2-60*246); sqrt 14824=121.75 \n" ); document.write( "x=(1/30)(293.75)=9.79 mph \n" ); document.write( "x=(1/30)(50.25)=1.675 mph, and that can't work because x-6 would be negative \n" ); document.write( " \n" ); document.write( "At 9.79 mph, it takes 4.19 hours outbound ANSWER 9.79 mph \n" ); document.write( "At 3.79 mph, it takes 10.82 hours inbound \n" ); document.write( "They add to 15.01, or 15 with rounding error. \n" ); document.write( " |