SOLUTION: A multiple-choice examination consists of 7 questions with possible answers of a, b, c, and d. Find the probability that a student gets at most 2 correct if he randomly guesses at

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Question 382890: A multiple-choice examination consists of 7 questions with possible answers of a, b, c, and d. Find the probability that a student gets at most 2 correct if he randomly guesses at each answer? Round your answer to four decimal places.
Answer by nyc_function(2741) About Me  (Show Source):
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7C0 (1/4)^0 (3/4)^7 + 7C1 (1/4)^1 (3/4)^6 + 7C2 (1/4)^2 (3/4)^5 =

(2187/16384) + (5103/16384) + (5103/16384) = (12393/16384) ≈ 0.7564