Question

A new computer virus can enter the system through e-mail or through the internet. There is a

30% chance of receiving this virus through e-mail. There is a 40% chance of receiving it
through the internet. Also, the virus enters the system simultaneously throughe-mail and the
internet with probability 0.15. What is the probability that the virus does not enter the system at
all?

Answer 1

100% - 30% - 40% - 15% = 15% chance that the virus does not enter the system at all