Christine has always been weak in mathematics Based on her p

Christine has always been weak in mathematics. Based on her performance prior to the final exam in Calculus, there is a 39% chance that she will fail the course if she does not have a tutor. With a tutor, her probability of failing decreases to 9%. There is only a 49% chance that she will find a tutor at such short notice.

Christine ends up failing the course. What is the probability that she had found a tutor? (Round your answer to 4 decimal places.)

Solution

B.) 22.1719% of not getting a tutor

49% getting a tutor * 9% fail rate = 4.41%

51% not getting a tutor * 39% fail rate = 19.89%

4.41 / 19.89 = 22.1719% of not getting a tutor