Sara drives 425 miles in 6 hours and 45 minutes. What is her average rate of speed? Round your answer to the nearest whole number.

Answer: 63 miles per hour (mph)

6 hours + 45 minutes = 6 hrs + 0.75 hrs = 6.75 hrs

Divide the distance (425 miles) over the time (6.75 hours) to get the speed. You must convert the time value to a single unit rather than a mixed unit of hours and minutes. So we get 425/6.75 = 62.96926 which rounds to 63