Answer: 1/252
Step-by-step explanation:
The probability of getting exactly 12 questions wrong on a multiple choice test with 20 questions and 5 choices per question is 1/252. This is calculated by using the binomial probability formula, which is P(x) = nCx * p^x * q^(n-x), where n is the number of trials (20 in this case), p is the probability of success (1/5 in this case) and q is the probability of failure (4/5 in this case). Therefore, P(12) = 20C12 * (1/5)^12 * (4/5)^8 = 1/252.