Question

It took Jill two hours to drive 100 miles. what was her average speed?

Answer 1

A possible solution could be 50MPH. Meaning, "Miles Per Hour".  If Jill was driving for two hours, and traveled a total of 100 miles within those two hours, then she would have had to been going 50 miles per hour.  So her average speed would be 50 miles per hour.  

Answer 2

Average speed is 50 mph