Since we know the x and y, you would divide 480 by 15 and 32 miles per hour. Then you would multiply 7.2 by 32 and get 230.4. Your trying to find with wind and against wind so just times that by two and get 460.8. I think
An=-31+(n-1)-11 find the eleventh term
a11 = -31 + (-11) (11-1)
a11 = -31 +-11(10)
a11 =-31 +-110
a11 = -142
Answer:
The probability that the proportion of books checked out in a sample of 412 books would differ from the population proportion by less than 4% is P=0.9255.
Step-by-step explanation:
The population's proportion is 
If we take a sample of 412 books (n=412), we have a standard deviation of the sampling distribution of:

We have to calculate the probabilty that the sample proportion will be between 0.25 and 0.33.

If you look at the attached graphic, you will see that the altitude (or height) of an equilateral triangle is:
Height = side length * sq root (3) / 2
Area = side^2 * sq root (3) / 4