The Two-Rivers Oil Company near Pittsburgh transports gasoline to its distributors by truck. The company recently contracted to supply gasoline distributors in souther Ohio, and it has 600,000 available to spend on the necessary expansion of its fleet of gasoline tank trucks. Three models of gasoline tank trucks are available. Super Tank, Regular Line, Econo-Tanker. Super Tank capacity gallons are 5,000 purchase cost is 67,000 and Monthly operating cost are 550. Regulare capacity gallons are 2,500 purchase caost is 55,000 and the monthly operating cost is 425. Econo-Tanker capacity gallons are 1000 purchase cost is 46,000 and the monthly operating cost is 350. The company estimates that the monthly demand for the region will be 550,000 gallons of gasoline. Because of the size and speed differences of the trucks the number of delieveries or round trips possible per month for each truck model will vary. Trip capacities are estimated at 15 trips per month for the super tanker, 20 trips per month for the regular line, and 25 trips for the Econo Tanker. Based on maintenance and driver availability the firm does not want to add more than 15 new vehicles to its flee. in, addition, the company has decided to purchase at least three of the new Econo-Tankers for use on short-run, low-demand routes. As a final constraint, the conpany deos not want more than half the new models to be Super Tankers.
A) if the company wishes to satisfy the gasoline demand with minimum monthly operating expense, how many many models of each truck should be purchased?
B) if the company did not require at least three Econo-Tankers and did not limit the number of Super Tankers to at most half the new models, how many models of each truck should be purchased?