A multiple-choice question has 5 options of which only one is correct. If a student does home work, then he is sure to identify the correct answer, otherwise the answer is chosen at random. Let A be the event that the student does his home work and B be the event that the student answers correctly. If P A = 2 3 , then P A B is equal to

Question

A multiple-choice question has 5 options of which only one is correct. If a student does home work, then he is sure to identify the correct answer, otherwise the answer is chosen at random. Let A be the event that the student does his home work and B be the event that the student answers correctly. If P A = 2 3 , then P A B is equal to, 10 11, 4 5, 3 7, 6 7

MARKS App · Accepted Answer

P B A c = 1 5 , P A = 2 3 P A B = P A ∩ B P B = P A ⋅ P B A P A P B A + P A c P B A c = 2 3 × 1 2 3 × 1 + 1 3 × 1 5 = 10 11

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