Problem 4. (problem 5.23 page 74) A company's management is worried about employee drug use and is instituting a policy.r of mandatory drug test. If an employee is a drug user, there is an 85% chance that he or she will test positive. If the employee is not a drug user, there is 95% chance that he or she will test negative. Individuals who test positive are red. We don't [mow the fraction of employees who are drug users. We do know, however that 10% of all employees tested positive. a. What fraction of employees are drug users? h. Of those who tested positive, what fraction are in fact not drug users