A quiz consists of 10 multiple-choice questions, each with 5 possible answers but only one is correct. For someone who makes random guesses for all of the answers, find the probability of passing if the minimum passing grade is 60 %.

P(each question is correct ) =1/5

This is a Binomial distribution with P(S) = 1/5 and P(F) = 4/5

Hence P( x= 6)= 10 C 6 (1/5)^6 * (4/5)^4

= 10 x 9 x 8 x 7/ 4! x 1/15625 x 256/625

= 210 x 256/15625 x 625

=0.0055

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