Answer:
b. Because the probability of being 15 or more correct is 0.0207, it is likely that she is just guessing at the questions.
Step-by-step explanation:
-This is a binomial probability distribution with p=0.5, n=20 and x=15.
The function is expressed as:

We calculate the probability of guessing 15 or more correctly:

The probability of passing, guessing 15+ correctly, is 0.0207. This probability is very low and it is it is likely that she is just guessing at the questions
W=12 would be the correct answer. I got this because if you divided 12 by 2, (12/2) you would get 6!
False, 24 x 10 x 90 = 21,600, 90 x 2,400 = 216,000