The employees of a firm that manufactures insulation are being tested for indications of asbestos in their lungs. The firm is requested to send three employees who have positive indications of asbestos on to a medical center for further testing. If 40% of the employees have positive indications of asbestos in their lungs, answer the following two questions. (a) Find the probability that ten employees must be tested in order to find three positives. (b) If each test costs $20, find the expected value and variance of the total cost of conducting the tests necessary to locate the three positives.