The first indianapolis 500 auto race took place in 1911. the winning car covered the 500 miles in 6.7 hours. what was the winning cars average rate of speed in miles per hour?

Average speed = (distance covered) / (time to cover the distance)

                         =        (500 miles)      /    (6.7 hours)

                         =            (500 / 6.7)  (mile/hour)

                         =                    74.63 miles per hour.

I imagine there were quite a number of pit stops included in that.

This is faster than I expected when I first read your question.
That's really gettin' with it for cars in 1911 !