Acertain virus infects one in every 300 people. a test used to detect the virus in a person is positive 85% of the time if the person has the virus and 10% of the time if the person does not have the virus. (this 10% result is called a false positive.) let a be the event "the person is infected" and b be the event "the person tests positive".
(a) find the probability that a person has the virus given that they have tested positive, i. e. find p(a|b). round your answer to the nearest tenth of a percent and do not include a percent sign.
(b) find the probability that a person does not have the virus given that they test negative, i. e. find p(a'|b'). round your answer to the nearest tenth of a percent and do not include a percent sign.