document.write( "Question 353877: Sally drove from Town A to Town B at an average speed of 20 miles per hour. She then returned to Town A along the same road at an average speed of 30 miles per hour. What was Sally’s average speed, in miles per hour, for the entire trip?
\n" ); document.write( " \n" ); document.write( "
Algebra.Com's Answer #472213 by kintosh88(1)\"\" \"About 
You can put this solution on YOUR website!
Ok so with this you need to do a little algebra to get you answer.
\n" ); document.write( "we are missing the time and distance.
\n" ); document.write( " let just say the distance for both trip is d+d or 2d\r
\n" ); document.write( "\n" ); document.write( "Now using the rate problem we will get the time by itself\r
\n" ); document.write( "\n" ); document.write( "d = r.t and t= d/r\r
\n" ); document.write( "\n" ); document.write( " so now we will find time for both trips : t = d/r + d/r
\n" ); document.write( " t= d/20 +d/30
\n" ); document.write( " = 3d/60 + 2d/30
\n" ); document.write( " = 5d/60
\n" ); document.write( " = d/12\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now that we have the time lets find the average distance\r
\n" ); document.write( "\n" ); document.write( " Average distance = distance / time
\n" ); document.write( " = 2d / d/12
\n" ); document.write( " = 2d x12/d
\n" ); document.write( " =24d/ d
\n" ); document.write( " your answer will be 24.\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
\n" );