document.write( "Question 425343: A train goes from boston to new york averaging 40 km per hour and returns averaging 60 km per hour. what is the average speed for the round trip? \n" ); document.write( "
Algebra.Com's Answer #296208 by ankor@dixie-net.com(22740) You can put this solution on YOUR website! A train goes from boston to new york averaging 40 km per hour and returns averaging 60 km per hour. what is the average speed for the round trip? \n" ); document.write( ": \n" ); document.write( "Let a = speed for the whole trip \n" ); document.write( "let d = the one way distance \n" ); document.write( ": \n" ); document.write( "Write a time equation, Time = dist/speed \n" ); document.write( "from time + to time = total time \n" ); document.write( " \n" ); document.write( "Multiply by 120a, results \n" ); document.write( "3ad + 2ad = 120(2d) \n" ); document.write( "5ad = 240d \n" ); document.write( "Divide both sides by d \n" ); document.write( "5a = 240 \n" ); document.write( "a = \n" ); document.write( "a = 48 km/hr is the av for the round trip \n" ); document.write( " |