Of the participants in a corporate meeting, 20% have had Red Cross training in cardiopulmonary resuscitation (CPR). During a break in the session, one par- ticipant is randomly selected to go across the street and pick up some hoagies from the local deli. A patron at the deli is stricken by a severe heart attack. His survival probability is just 0.40 if he does not receive immediate CPR, but will be 0.90 if CPR can be administered right away. The meeting participant and the stricken person are the only customers in the deli, and none of the employees knows CPR.
a. Without additional information, what is the probability that the stricken patron will survive?
b. Given that the stricken patron survives, what is the probability that the meeting participant knew how to administer CPR?
c. Given that the stricken patron does not survive, what is the probability that the meeting participant knew how to administer CPR?