Question

. There are n questions on a multiple choice exam, and for each question, there are four choices. To pass the exam, one must correctly answer at least 70% of the questions. The student has not studied, so he/she has to resort to guessing on every question.

a. Find the probability of the student passing for n = 10.

b. Find the expected number of questions answered correctly for n = 20.

c. Find the variance for the number of questions answered correctly for n = 10.

d. Find the minimum value of n such that the probability of the student getting a less than perfect score is greater than 0:99999.

e. Find the minimum value of n such that the probability of the student getting better than a zero (at least one correct) is greater than 0:99999.

Answer 1

thank you