SOLUTION: if you travel from point a to point b at 20 miles an hour and you return at 40 miles an hour what is your ave speed?

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Question 762423: if you travel from point a to point b at 20 miles an hour and you return at 40 miles an hour what is your ave speed?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
It seems obvious, but you should always use the
equation:
average speed = ( total distance ) / ( total time )
Let +d+ = the one-way distance
Let +t+ = the total time
----------------------
+t+=+d%2F20+%2B+d%2F40+
again:
average speed = ( total distance ) / ( total time )
average speed = +2d+%2F+%28+d%2F20+%2B+d%2F40+%29+
Divide through by +d+
average speed = +2+%2F+%28+1%2F20+%2B+1%2F40+%29+
average speed = +2+%2F+%28+4%2F80+%2B+2%2F80+%29+
average speed = +%28+80%2F6+%29%2A2+
average speed = +26.667+ mi/hr