Fast-food businesses can now choose between hiring workers to take customer orders or employing touchscreens for customers to directly enter order information. Assume customers are indifferent between the two methods of placing orders. A worker tends to be faster at taking orders, with the average order taking 3 minutes. When using a touchscreen, it takes on average 5 minutes per order. There is also a cost difference. A worker costs $15 per hour, and the cost of touchscreens comes to a cost of $12 per hour.

If the business wants to take a certain number of orders per hour, which input (touchscreens or workers) would you recommend minimizing the cost of taking orders? Briefly explain your reasoning using terminology and any relevant principle(s) from this class. (Two or three sentences are sufficient.