A poultry farmer vaccinated 540 of his 720 chickens against a disease. Two months later, 5% of the vaccinated and 80% of the unvaccinated chicken, contracted the disease.

Question

A poultry farmer vaccinated 540 of his 720 chickens against a disease. Two months later, 5% of the vaccinated and 80% of the unvaccinated chicken, contracted the disease.
Calculate the probability that a chicken chosen random contracted the disease.

Steve · Answer

(.05*540 + .80*(720-540))/720 = 23.75%