A company has made available to its employees (without charges) extensive club facilities that may be used before work, during the lunch hour, after work, and on weekends. The record for the last year indicates that of 250 employees, 110 used the facilities at times. Of 170 males employed by a company, 65 used the facilities. What is the probability that an employer chooses at random (setup contingency table) 

a) is a female or has used the health club facilities 

b) is a male and has not used the health club facilities 

c) suppose that we select the female employees of the company. What then is the probability that she has used the health club facilities.