A chemical manufacturer wants to lease a fleet of 22 railroad tank cars with a combined carrying capacity of 312 comma 000 gallons. Tank cars with three different carrying capacities are available: 6 comma 000 gallons, 12 comma 000 gallons, and 24 comma 000 gallons. Letting tequalsnumber of 24 comma 000 railroad tank cars in the fleet, 2tnegative 8 6 comma 000-gallon railroad tank cars, and minus3tplus30 12 comma 000 gallon railroad tank cars will be in the fleet for a certain range of t. The cost of leasing a 6 comma 000-gallon tank car is $250 per month, a 12 comma 000-gallon tank car is $750 per month, and a 24 comma 000-gallon tank car is $1050 per month. Which of the solutions to the number of each type of tank car in the fleet would minimize the monthly leasing cost?