The following table classifies 500 people who are given the Covid-19 test by their Covid-19 test positive or negative and by whether or not have Covid-19 virus. B1: Have Covid-19 B2: Does not have Covid-19 virus virus A1: Test positive 115 75 A2: Test Negative 25 285 If one of these 500 people is selected randomly, find the following probabilities: (a) (2.5 pts) P(A2 U B2) (b) (2.5 pts) P (B1 | Al)