Nathan has an infection and he needs to be treated with penicillin But there’s a 75% probability of him being allergic to penicillin And to test if the skin reacts to penicillin, the test is 98% accuracy So even if he has the allergy the test is only 98% accurate of identifying the allergy Therefore we are asked to find the probability of both these events happening Event 1 and event 2 both should happen then. When the ‘and’ function is used in probabilities then the probabilities of both events happening should be multiplied Therefore probability that Nathan has the allergy and test predicts it is = 75% x 98% = 0.735 The answer is D. 0.735
