multiple choice test consists of seven questions with five choices each of which only one is correct. If a student guesses on all questions the probability that a student gets exactly 3 correct answers is given by 7C3 . (3/5)3 . (2/5)4 7C5 . (1/3)5 . (2/3)2 7C5 . (1/5)3 . (4/5)4 7C3 . (1/5)3 . (4/5)4
Added by Randall S.
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This can be done using combinations, which is denoted as 7C3. Show more…
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