6. In both Mr. Jacquez's Math 2 classes, Period 2 and Period 3 were given the same test. The table below shows the results from the two classes.
a. Find the probability that a randomly selected student from Period 2's class failed the test.
b. Find the probability that a randomly selected student who failed the test is from Period 3's class.
*would help out big time if someone could help me out, thankyou*