California University encourages professors to consider using e-textbooks instead of the traditional paper textbooks. Many courses have adopted the new e-textbook option. Suppose that the random variable X represents the number of courses taken by a student during the Fall 19 semester at California University that provide an e-textbook option. The (partial) probability distribution for the random variable X is provided.
X = # course with e-text option 0 1 2 3 4 5
Probability 0.30 0.25 0.15 0.10
(a) Assume we randomly select 7 students at California University who are enrolled in courses this Winter semester. What is the probability that exactly 3 students reported taking 2 or more courses that offer an e-textbook option this Winter semester?