A multiple choice test has 7 questions each of which has 5 possible answers, only one of which is correct. If Judy, who forgot to study for the test, guesses on all questions, what is the probability That she will answer exactly 3 questions correctly?

A) 0.115
B) 0.885
C) 0.275
D) 0.00800

Question

A multiple choice test has 7 questions each of which has 5 possible answers, only one of which is correct. If Judy, who forgot to study for the test, guesses on all questions, what is the probability That she will answer exactly 3 questions correctly?

A) 0.115
B) 0.885
C) 0.275
D) 0.00800

Quizplus · Accepted Answer

The probability of guessing a question correctly is 1/5, and incorrectly is 4/5. Using the binomial probability formula for exactly 3 correct answers out of 7, we calculate: C(7,3) * (1/5)^3 * (4/5)^4 = 0.115.

A Multiple Choice Test Has 7 Questions Each of Which