Question

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

Answer 1

average speed is 50 mph

Answer 2

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.