a) Let X and Y are events in a sample space and suppose that P(X")=0.30, P(Y)=0.75, and P(X'U Y')=0.4. What is P(XU Y)? (4 marks) b) Five people have been exposed to Corona virus. Once exposed, a person has a 50-50 chance of actually becoming ill. i. What is the probability that exactly one of the people becomes ill? (3 marks) ii. What is the probability that none of the five people becomes ill? (2 marks)