Use the following information to answer each part of this question. For each part of this question, show a suitable number of middle steps using the formula for binomial distribution. Problem: You write a 20-mark multiple-choice quiz with 5 possible answers for each question (A, B, C, D, or E) by guessing at each answer. (a) Determine the probability of getting exactly 15 answers correct. (b) Determine the probability of getting at least 18 answers correct