A shipping company is buying new trucks. The high-capacity trucks cost 550,000 and hold 320 cases of merchandise. The low-capacity trucks cost $30,000 and hold 220 cases of merchandise. The company has budgeted $1,080,000 for the new trucks and has a maximum of 30 people qualified to drive the trucks. Due to availability limitations, the company can purchase at most 18 high-capacity trucks. How many of each type of truck should the company purchase to maximize the number of cases shipped at one time?
To maximize the number of cases of merchandise that can be shipped simultaneously, the company should purchase ___ high-capacity trucks and ___ low-capacity trucks.