The probability that meditation will reduce heart attack is given by 0.30. Then why are we multiplying 0.70 instead of 0.30 with 0.40?
Here, in the question they have given that the heart attack is reduced by 30% by meditation and yoga. But , we are asked to find the probability that a person suffers from heart attack even though he has gone through meditation and yoga. So we multiply with 70%(chance of occuring heart attack).