A company offers a basic life insurance policy to its employees, as well as a supplemental life insurance policy. To purchase the supplementa policy, an employee must first purchase the basic policy. Let X denote the proportion of employees who purchase the basic policy, and Y the proportion of employees who purchase the supplemental policy. Let X and Y have the joint density function f(x,y)= 2(x+y). Given that 10% of the employees buy the basic policy, what is the probability that fewer than 5% buy the supplemental policy?
