(2 points) Consider the LP (using urs variables) The Niner Bus department currently employees 50 drivers. In the coming 5 years they are going to need at least 60, 70, 50, 65, and 75 (respectively) drivers (having too many is acceptable, but not too few) The annual salary for a driver is 10 (units of $ 1000) while it costs 4 to recruit a driver and it costs 8 to release a driver. Formulate and solve the LP (using urs variables as described in the hint) to determine the minimum cost. The minimum 5 year total cost for paying and hiring/firing drivers is Hint: Let X1, X2, X3, X4, X5 be the decision variables for the number of drivers to be hired (fired if negative) at the beginning of year i. A useful optional variable is d; for the number of drivers working in year i. Clearly d2 = d1 + x2. the formula for z will be 10 %-1 d; +4 -1 x} +8 %-1 x