Question 578768: A four-question multiple choice quiz with choices A, B, C, D, and E. If a person taking the quiz guessed all four questions, find:
P( exactly two correct)
Answer by dfrazzetto(283)   (Show Source):
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5 choices, therefore P(correct) for any independent question is 1/5:
P(exactly 2 correct) = P(2 correct)x P(2 wrong)
= (1/5)(1/5) x (4/5)(4/5)
= .04 x .64 = .0256 = roughly 2.6% chance
There is a 4 % chance that he/she gets at least 2 correct, so the probability for getting two and ONLY two correct, should be lower, since less outcomes satisfy the conditions.
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