document.write( "Question 376588: During the first part of a trip, a canoeist travels 71 miles at a certain speed. The canoeist travels 12 miles on the second part of the trip at a speed 5 mph slower. The total time for the trip is 5 hours. What was the speed on EACH part of the trip? \n" ); document.write( "
Algebra.Com's Answer #267955 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! During the first part of a trip, a canoeist travels 71 miles at a certain speed. \n" ); document.write( " The canoeist travels 12 miles on the second part of the trip at a speed 5 mph slower. \n" ); document.write( " The total time for the trip is 5 hours. What was the speed on EACH part of the trip? \n" ); document.write( ": \n" ); document.write( "Let s = speed for the 1st part of the trip \n" ); document.write( "then \n" ); document.write( "(s-5) = speed on the 2nd part of the trip \n" ); document.write( ": \n" ); document.write( "Write time equation; time = dist/speed \n" ); document.write( ": \n" ); document.write( "1st speed time + 2nd speed time = 5 hrs \n" ); document.write( " \n" ); document.write( "Multiply by s(s-5) to clear the denominators, results: \n" ); document.write( "71(s-5) + 12s = 5s(s-5) \n" ); document.write( "71s - 355 + 12s = 5s^2 - 25s \n" ); document.write( "83s - 355 = 5s^2 - 25s \n" ); document.write( "0 = 5s^2 - 25s - 83s + 355 \n" ); document.write( "5s^2 - 108s + 355 = 0 \n" ); document.write( "Use the quadratic formula to find s \n" ); document.write( " \n" ); document.write( "Where x = s; a=5; b=-108; c=355 \n" ); document.write( " \n" ); document.write( ": \n" ); document.write( " \n" ); document.write( ": \n" ); document.write( " \n" ); document.write( "two solutions \n" ); document.write( " \n" ); document.write( "s = \n" ); document.write( "s = 17.5557 \n" ); document.write( "and \n" ); document.write( " \n" ); document.write( "s = \n" ); document.write( "s = 4.0443 \n" ); document.write( ": \n" ); document.write( "s = 17.5557 mph is the only reasonable speed for the 1st part of the trip \n" ); document.write( "and \n" ); document.write( "17.5557 - 5 = 12.5557 mph is the speed on the 2nd part of the trip \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "See if this is true, find the time at each speed \n" ); document.write( "71/17.5557 = 4.044 hrs \n" ); document.write( "12/12.5557 = .9557 \n" ); document.write( "------------------- \n" ); document.write( "total time: 4.9997 ~ 5 hrs \n" ); document.write( " |