There is an 80% chance that a prospective employer will check the educational background of a job

Question:

There is an 80% chance that a prospective employer will check the educational background of a job applicant (based on data from the Bureau of National Affairs, Inc.). Sixty-four job applications are randomly selected.
a. Find the probability that at least 50 of the applicants have their educational backgrounds checked.
b. Find the probability that exactly 50 of the applicants have their educational backgrounds checked.