Probability

Question

A certain disease is spread by only direct contact. The probability of a healthy person to get infected by a single direct contact is 0.02. What is the chance that a healthy person gets infected with the disease by the fourth time he comes into contact with an infected person? (assume contact with the other person is independent)

Answer 1

p(1st or 2nd or 3rd or 4th) = P(1st) + P(2nd) + P(3rd) + P(4th) = 4 X 0.02 = 0.08