An unprepared student takes five-questions of true-false type quiz and guesses every answer. What is the probability that the student will pass the quiz if at least four correct answers is the passing grade?

Question

An unprepared student takes five-questions of true-false type quiz and guesses every answer. What is the probability that the student will pass the quiz if at least four correct answers is the passing grade? (A) (1/16) (B) (3/16) (C) (1/32) (D) (3/32)

Tardigrade Admin · Accepted Answer

n = total number of ways = 25 = 32 Since each answer can be true or false m = favourable number of ways = 5C4 +5C5 =(5!/4!1!) + (5!/5!0!) =5+1=6 ⇒ m = 6 Since to pass the quiz, student must give 4 or 5 true answers Hence, P = (m/n) ⇒ p = (6/32) ⇒ P = (3/16)

Q. An unprepared student takes five-questions of true-false type quiz and guesses every answer. What is the probability that the student will pass the quiz if at least four correct answers is the passing grade?

$\frac{1}{16}$

$\frac{3}{16}$

$\frac{1}{32}$

$\frac{3}{32}$

Q. An unprepared student takes five-questions of true-false type quiz and guesses every answer. What is the probability that the student will pass the quiz if at least four correct answers is the passing grade?

161​

163​

321​

323​

n = total number of ways = 25=32 Since each answer can be true or false & m = favourable number of ways =5C4​+5C5​ =4!1!5!​+5!0!5!​=5+1=6⇒m=6 Since to pass the quiz, student must give 4 or 5 true answers Hence, P=nm​⇒p=326​⇒P=163​

$\frac{1}{16}$

$\frac{3}{16}$

$\frac{1}{32}$

$\frac{3}{32}$