18 points--show work
in a hospital there are 13 nurses and 6 physicians, 4 nurses and 5 physicians are females. if a staff person is selected, find the probability that the subject is a nurse or male.

Bill makes leather shoes. he charges $45 for a pair of women's shoes and $50 for a pair of men's shoes. he sells x pairs of women's shoes and y pairs of men's shoes each week and earns a total income of $2,500. this situation can be represented by the equation . if bill has no female customers during a particular week, he needs to sell pairs of men's shoes to earn his weekly income of $2,500.