SOLUTION: A student is taking a multiple choice exam with 16 questions. Each question has five alternatives. If the student guesses on 12 of the questions what is the probability she will

Algebra ->  Probability-and-statistics -> SOLUTION: A student is taking a multiple choice exam with 16 questions. Each question has five alternatives. If the student guesses on 12 of the questions what is the probability she will       Log On


   



Question 362042: A student is taking a multiple choice exam with 16 questions. Each question has five alternatives. If the student guesses on 12 of the questions what is the probability she will guess at least 8 correct?
Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
x=.8 and y=.2
Partly expand (x+y)^12
x^12+12x^11y+66x^10y^2220x^9y^3
=.7946 Probability 9 or more will be wrong.
1-.7946
=.2054 probability she will guess at least 8 correct.
.
Ed