document.write( "Question 6643: A man travel upstream at 8 miles per hour and downstream 12 miles and hour. This took him 2 hours to do. What is his average speed \n" ); document.write( "
Algebra.Com's Answer #3642 by prabhjyot(165)\"\" \"About 
You can put this solution on YOUR website!
The man travels upstream - 8 miles /hour
\n" ); document.write( "the man travels downstream - 12 miles\r
\n" ); document.write( "\n" ); document.write( "total distance covered = (8+12)=20 miles
\n" ); document.write( "total time for travelling this distance - 2 hours\r
\n" ); document.write( "\n" ); document.write( "Average speed = total distance/ time\r
\n" ); document.write( "\n" ); document.write( "Average speed = 20/2
\n" ); document.write( " average speed = 10 miles/hour\r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );