document.write( "Question 971470: Little red riding hood rides to grandmas house at 20 mph . She goes back on the same path at 35 mph . What is the average speed ? \n" ); document.write( "

Algebra.Com's Answer #593936 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Average speed is always:
\n" ); document.write( "[ total distance traveled ] / [ time to travel that distance ]
\n" ); document.write( "Let $\"+d+\"$ = one-way distance to grandma's house
\n" ); document.write( "----------------
\n" ); document.write( "Distance to house:
\n" ); document.write( " $\"+d+=+20t%5B1%5D+\"$
\n" ); document.write( "Distance going back:
\n" ); document.write( " $\"+d+=+35t%5B2%5D+\"$
\n" ); document.write( "--------------------
\n" ); document.write( "Ave speed:
\n" ); document.write( " $\"+2d+%2F+%28+t%5B1%5D+%2B+t%5B2%5D+%29+\"$
\n" ); document.write( " $\"+2d+%2F+%28+d%2F20+%2B+d%2F35+%29+\"$
\n" ); document.write( "Divide top and bottom by $\"+d+\"$
\n" ); document.write( " $\"+2+%2F+%28+1%2F20+%2B+1%2F35+%29+\"$
\n" ); document.write( "Multiply top and bottom by $\"+140+\"$
\n" ); document.write( " $\"+280+%2F+%28+7+%2B+4+%29+\"$
\n" ); document.write( " $\"+280%2F11+=+25.4545+\"$ mi/hr
\n" ); document.write( "Hope this makes sense\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );