An autobody shop needs to purchase two types of car jacks, an automatic electric one, or a gas-powered one. The automatic electric one can process 5 cars every hour and uses 6 units of electricity whereas the gas-powered one can process 4 cars each hour using 7 units of gas. Since there is a limit to how many automatic electric ones there can be due to the limited number of power outlets, the shop must use less than 15 automatic electric ones. The shop can use at most 50 units of electricity and 80 units of gas. How many of each type of jack should the shop purchase to maximize the amount of cars processed every hour?