document.write( "Question 530172: a train travels 180 miles in an hour less time than a bus traveling the same distance. if the speed of the bus is 15 mph slower that the speed of the train, find the speed of the train and bus? \n" ); document.write( "
Algebra.Com's Answer #349927 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! a train travels 180 miles in an hour less time than a bus traveling the same distance. \n" ); document.write( " if the speed of the bus is 15 mph slower that the speed of the train, find the speed of the train and bus? \n" ); document.write( ": \n" ); document.write( "Let s = speed of the bus \n" ); document.write( "then \n" ); document.write( "(s+15) = speed of the train \n" ); document.write( ": \n" ); document.write( "Write a time equation, time = dist/speed \n" ); document.write( ": \n" ); document.write( "Bus time - train time = 1 hr \n" ); document.write( " \n" ); document.write( "; \n" ); document.write( "multiply by s(s+15); results: \n" ); document.write( "180(s+15) - 180s = s(s+15) \n" ); document.write( "180s + 2700 - 180s = s^2 + 15s \n" ); document.write( ": \n" ); document.write( "a quadratic equation \n" ); document.write( "s^2 + 15s - 2700 = 0 \n" ); document.write( ": \n" ); document.write( "Factor to \n" ); document.write( "(s+60)(s-45) = 0 \n" ); document.write( ": \n" ); document.write( "the positive solution \n" ); document.write( "s = 45 mph is the speed of the bus \n" ); document.write( "then \n" ); document.write( "45 + 15 = 60 mph is the speed of the train \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "Check this by finding the times of each \n" ); document.write( "180/45 = 4 hrs \n" ); document.write( "180/60 = 3 hrs \n" ); document.write( "-------------- \n" ); document.write( "differ: 1 hrs \n" ); document.write( " |