Top Tool Company wishes to hire parttime models to pass out literature about its machine tools at an upcoming trade show. Each of the 6 available models can work 2 of the 5 show days: Monday–Tuesday, Monday–Wednesday, Monday–Friday, Tuesday–Wednesday, Tuesday–

Friday, and Thursday–Friday. If there is no more than one day separating their duty days, models will be paid $300, but the charge is $500 if two or more days intervene. Top Tool seeks a minimum cost way to have a least one model on all 5 days.

Do

(a) through

(d) as in Exercise 11-9 with the revised model minimizing the number of days uncovered using just 2 models.