Assume that the chances of the patient having a heart attack are
. It is also assumed that a meditation and yoga course reduce the risk of heart attack by
and prescription of certain drug reduces its chances by
. At a time a patient can choose any one of the two options with equal probabilities. It is given that after going through one of the two options the patient selected at random suffers a heart attack. Find the probability that the patient followed a course of meditation and yoga?