Question

On a multiple choice examination with three possible answers (out of which only one is correct) for each of the five questions, what is the probability that a candidate would get four or more correct answers just by guessing?

Answer 1

No. of questions = n = 5
Option given in each question = 3
p = probability of answering correct by guessing = 1/3
q = probability of answering wrong by guessing=1-p=1-1/3=2/3

This problem can be solved by binomial distribution.