“Average Speed “ v.s. “Average Number”

Average speed = total distance divided by total time= total distance / total time

1, chapter-coundown-19-2007(55)

Stan drove 300 miles in 5 hours, 20minutes.  Next, he drove 360 miles in 6 hours, 40 minutes.  What was Stan’s average speed in miles per hour for the total trip?

The average (arithmetic mean) is the sum of the values divided by the number of values.

Example : 5, 9, 10
Their sum is 5+9+10 = 24 and there are 3 numbers
The average is 24/3 = 8

1, school-sprint-20-2008(94)

Thomas took three 100-point quizzes, and the mean score for three quizzes was 87 points.  If the highest score is taken away, the mean of remaining two scores would be 83.5 points.  If the lowest score is taken away, the mean of the remaining two scores would be 89 points,  What is the highest score?

2, chapter-sprint -7-2007(1)

The mean of four distinct positive integers is 5,  If the largest integer is 13, what is the smallest integer?