What got kroc involved in the restaurant business?

Before launching his first McDonald´s restaurant, Ray Kroc was a salesman. Among other things, he sold a machine called "Multi Mixer" that could mix five milkshakes at the same time. He managed to sell 8 mixers to two brothers, the MacDonalds, that ran a small hamburger chain in California. MacDonald. There he saw how 40 milkshakes were being made at the same time. That was a defining experience. He was so impressed that decided to launch a business together with the brothers using the "MacDonald system."  The rest is just history.  

Explanation:

where is your diagram?

answer; the miracles;