A multiple-choice test has 30 questions and each one has five possible answers,of which one is correct.If all answers were guesses,find the probability of getting exactly four correct answers.
A).0604
B).1325
C).2552
D).8000

Question

Quizplus · Accepted Answer

The probability of guessing a correct answer for each question is 1/5, and the probability of guessing an incorrect answer is 4/5.

Using the binomial probability formula, we can calculate the probability of getting exactly 4 correct answers out of 30:

P(X = 4) = (30 choose 4) (1/5)^4 (4/5)^26

Using a calculator, we can simplify this to approximately 0.1325. Therefore, the best choice is B, with a probability of 0.1325.

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