An instructor gives a pop quiz consisting of 10 multiple choice questions, where each question has 5 choices, (a) through (d). What is the probability of

An instructor gives a pop quiz consisting of 10 multiple choice questions, where each question has 5 choices, (a) through (d). What is the probability of passing the pop quiz if you guess the answers? Passing means getting 8 out of 10 questions correct.

 

p = 0.2   q=0.8

 

P(at least 8 correct)

= P(8 correct)+P(9correct)+P(10 correct)

=  10C8*0.8⁸*0.2²   +    10C9*0.8⁹*0.2¹     +     10C10*0.8¹⁰*0.2⁰

=  45  *0.8⁸ * 0.04   +    10  *0.8⁹ * 0.2     +     0.8¹⁰

^{=      You can finish it :)}