1. The problem statement, all variables and given/known data In a certain high-risk group, the chance of a person having suffered a heart attack is 70%. If four persons are chosen from the group, find the probability that at least one will have had a heart attack. 2. Relevant equations (work shown below) these would be dependent 3. The attempt at a solution (.7)/(4) = 2.8
It might be easier to think of the chance that a specific individual doesn't have a heart attack, so what are the chances that none of the individuals have heart attacks (and you might want to rethink the dependence).
your answer is wrong i don think it is a dependent event the probability of a person with heart attack is 0.7 so the probability that among 4 at least 1 has heart attack = 1 - probability that none have = 1 - (0.3)[itex]^{4}[/itex] must be correct but verify it
Amateur's answer is correct. Your attempt doesn't make any sense. Remember: probability can never be more than 1. So if you find 2.8, think again.