We have the frequencies for each of the grades. We can estimate the number of students graded by adding all those frequencies. Let's call N the total number of grades:

We have then a total number of grades of 39.
The corresponding relative frequency for a grade is the ratio of the frequency to the total number of "samples", 39 in this case.
Then, for grade A, the relative frequency (RF) will be:

This will be the fraction of the total grades that are A. Represented as a percentage will be 10.26%, rounded to two decimal places.
Now, to complete the table we do the same for the other frequencies:
For grade B:

For grade C:

For grade D:

For grade F:
 
 
        
             
        
        
        
Answer:
A
Step-by-step explanation:
 
        
                    
             
        
        
        
P = 2m + 2w
Add -2w on both sides of the equations
2m = p - 2w
Divide both sides by 2
2w = p      =      2m
 / 2                      /2
m = 1 / 2 p - w