A multiple-choice test has 30 questions and each one has five possible answers, of which only one is correct. If all answers were guesses, find the probability of getting exactly four correct answers.
A) .1227
B) .1325
C) .0604
D) .0374

Question

Quizplus · Accepted Answer

Probability of getting question correct = .2. Four successes in 30 trials. Treat as a binomial. P(X) = n!/[x!(n − x)!] × p^x(1 − p)ⁿ⁻^x, for x = 4, when p = .20 and n = 30.

A Multiple-Choice Test Has 30 Questions and Each One Has