The probability that a student correctly answers on the first try (the event A)
ID: 3205939 • Letter: T
Question
The probability that a student correctly answers on the first try (the event A) is P(A) = 0.3. If the student answers incorrectly on the first try. the student is allowed a second try to correctly answer the question (the event B). The probability that the student answers correctly on the second try fives that he angered incorrectly on the first try is 0.6. Find the probability that the student correctly answers the question on the first or second try. a) 0.72 b) 0.51 c) 0.90 d) 0.34 e) 0.18 f) None of the above.Explanation / Answer
Solution:- (a) The probability that the student correctly answers the question on the first or second try =0.72
The probability of correctly answering the question on the first try is 0.3
The probability of incorrectly answering on the first try = 0.7
The probability of answering correct on second anwer given that he answered incorrectly on first try = 0.7 × 0.6 = 0.42.
The probability that the student correctly answers the question on the first or second try = 0.3 + 0.42 = 0.72
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