document.write( "Question 930733: Genny travels from one elementary school to another and back at a rate of 20 miles per hour one way and 30 miles per hour another way. What is her average rate of speed for both trips? \n" ); document.write( "
Algebra.Com's Answer #565250 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! Genny travels from one elementary school to another and back at a rate of 20 miles per hour one way and 30 miles per hour another way. \n" ); document.write( " What is her average rate of speed for both trips? \n" ); document.write( ": \n" ); document.write( "let d = the one way distance of the trip \n" ); document.write( "let a = the average speed for the round trip \n" ); document.write( ": \n" ); document.write( "Write a time equation; time = dist/speed \n" ); document.write( "to time + return time = total time \n" ); document.write( " \n" ); document.write( "multiply equation by 60a; cancel the denominators \n" ); document.write( "3ad + 2ad = 60(2d) \n" ); document.write( "5ad = 120d \n" ); document.write( "divide both sides by d \n" ); document.write( "5a = 120 \n" ); document.write( "a = 120/5 \n" ); document.write( "a = 24 mph is the average for the round trip \n" ); document.write( " \n" ); document.write( " |