A computer virus which is known to infect 3.5% of files has been detected on your system. You have decided to use a virus checker which is 96% reliable when scanning infected files and 99.2% reliable for files that are not infected. Consider a file which is marked as infected. Knowing that sometimes the test may be wrong, what is the probability that the file is indeed infected with the virus? You must explicitly show the steps you followed to arrive at your answer.