A process consists of a fast oven and a slow oven working at the same time, followed by a packing and billing operation. Each oven processes batches of 6 cookies at a time. Each batch takes 10 minutes to bake on the faster oven, and 15 minutes to bake on the slower oven. After baking, each batch of 6 cookies is packed into a box, and a receipt is printed out and placed in the box. The packing and receipt generation and placement operations take 4 minutes per box. Calculate the capacity of the process in boxes per hour. Please show all your work.