Question

Assume that the chances of a patient having a heart attack is 40%. Assuming that a meditation and yoga course reduces the risk of heart attack by 30% and prescription of certain drug reduces its chance by 25%. 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.

Answer 1

Let A, E₁ and E₂ respectively be the events that a person has a heart attack, the selected person followed the course of yoga and meditation and the person adopted the drug prescription.

P (A) = 40/100 = 0.40, P(E₁) = P(E₂) = 1/2

P(A/E₁) = 0.40 × 0.70 = 0.28, 

P(A/E₂) = 0.40 × 0.75 = 0.30

Probability that the patient suffering from heart attack followed the course of meditation and yoga is