A student takes a 6 question multiple choice quiz with 4 cho

A student takes a 6 question multiple choice quiz with 4 choices for each question. If the student guesses at random on each question, what is the probability that the student gets exactly 4 questions correct?

Solution

P(correct answer ) = 1/4 = 0.25

P(wrong answer) = 1 - 1/4 = 3/4 = 0.75

P(3 questions correct) = 4C3 * (0.25)^3 * (0.75)^3 = 0.046875