Answer:
The average velocity the entire trip was 43.25 mi/h
Step-by-step explanation:
In this case we have to calculate an average based on the miles traveled. First we have to calculate the total of miles traveled, then calculate the portion of the total travel of each and with this calculate the average speed during the trip. First the total miles traveled:

Now the percentages:
At 57 mi/h were 
At 44 mi/h were 
At 37.8 mi/h were 
Now multiplying the speed by the portion and summing them we can have the average velocity:

The average velocity the entire trip was 43.25 mi/h
Answer:
B. The intervals are centered around the sample mean GPA.
D. 95% of the intervals will contain the population mean in the long run.
Step-by-step explanation:
Confidence interval:
Depends on two things: The sample mean and the margin of error.
Lower end: Sample mean - margin of error
Upper end: Sample mean + margin of error
This means that the intervals are centered around the sample mean.
x% level:
x% of the intervals will contain the population mean in the long run.
So the true statements are:
B. The intervals are centered around the sample mean GPA.
D. 95% of the intervals will contain the population mean in the long run.
8 3/4 x 8 = 64 24/4
70 inches