Answer:
62.17% probability that a randomly selected exam will require more than 15 minutes to grade
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean  and standard deviation
 and standard deviation  , the zscore of a measure X is given by:
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:

What is the probability that a randomly selected exam will require more than 15 minutes to grade
This is 1 subtracted by the pvalue of Z when X = 15. So



 has a pvalue of 0.3783.
 has a pvalue of 0.3783.
1 - 0.3783 = 0.6217
62.17% probability that a randomly selected exam will require more than 15 minutes to grade
 
        
             
        
        
        
Hello,
there are some words that I could not read. But:
I support evements are independants.
p(s)=0.2
p(l)=1-0.2=0.8 l=lose
1)0.8*0.2=0.16
2) 0.8²*0.2=0.128
3) 0.8^3*0.2=0.1024
4) 0.2*0.8^(n-1)
        
             
        
        
        
ANSWER: (5,2) 
according to the graph, the vertices of the
curve are 5 in abscissa and 2 in ordinate
hence the vertex (5,2)
        
             
        
        
        
I do believe the correct and is 9 inches 
        
                    
             
        
        
        
Answer:
3
Step-by-step explanation:
Slope =y2−y1 divided to x2−x1
8−2
4−2
6/2
= 3
Hope this helped :)
Have a good one