Summer Assignment #2 Hints

I'll update this post as I answer more questions about the word problems...

#9.  This is one of the toughest ones on the assignment.  It is tempting to average the two speeds together.  However, it's not really "fair" to average them, since, logically, the person spent more time walking at the slower speed than at the faster speed.

To get an average speed, you need a total distance divided by a total time.  Since the actual distance was not given you will have to treat it as an unknown, for example, call it "X."

The average speed is the total distance there and back (2X) divided by the total time.  How do you get the total time?  Figure it out knowing the individual speeds!  For example, if I walked at a speed of 2.4, then my time spent was X/2.4.