In answering a question on a multiple choice test

MATHEMATICS · Subjective · CBSE · Mathematics · Probability · Probability

Problem

4. In answering a question on a multiple choice test, a student either knows the answer or guesses. Let

\frac{3}{4}

be the probability that he knows the answer and

\frac{1}{4}

be the probability that he guesses. Assuming that a student who guesses at the answer will be correct with probability

\frac{1}{4}

. What is the probability that the student knows the answer given that he answered it correctly?