There are two streams flowing past an industrial plant. The dissolved oxygen, DO, level in the water downstream is an indication of the degree of pollution caused by the waste dumped from the industrial plant. Let A denote the event that stream a is polluted and B denote the event stream b is polluted. From measurements taken last year it was determined that Probability of A is 0.5, Probability of B is 0.3 and probability that at least one stream is polluted is 0.71.
A. Determine the probability that both the streams are polluted.
B. Determine the probability that stream b is also polluted given that stream a is polluted
C. Determine the probability that stream a is polluted given that at least one of the streams is polluted