Question

1.) Determine the probability that in a group of 3 people, none of them die from heart disease or cancer

2.) Determine the probability that in a group of 3 people, at least one of them die from heart disease or cancer, and explain why it is so difficult to calculate this probability directly yet so easy to calculate it using a trick.

Odds of dying from Heart disease AND cancer are 1 in 7

Answer 1

This is a binomial distribution question with
n = 3
p = 0.125
q = 1 - p = 0.875
where


It is difficult to calculate the probability directly because we have to calculate the probability for 3 events (i.e. x=1,2,3), while if we calculate using the trick as we used in our calculation we had to calculate probability of only one event (i.e. x=0).

Please hit thumps up if the answer helped you