Binomial Probability Distribution

Question

You are taking a quiz with 3 multiple-choice questions. Each question has 6 choices, and only one of which is correct. Assume that you guess the answers to all questions.

Use the multiplication rule to find the probability that the first two guesses are wrong and the third is correct. That is, find P(WWC)P(WWC), where C denotes a correct answer and W denotes a wrong answer. 

P(WWC)=

What is the probability of getting one correct answer and 2 wrong answers when 3 guesses are made? 

Answer 1

Since each event is independent, P(WWC) = P(W)P(W)P(C). In this case, P(W) = 5/6, since there are 5 wrong answers and 1 correct one, and P(C) = 1/6 for the same reason.

In this case P(WWC) = 5/6 * 5/6 * 1/6 = 25/216.