Kristen’s Cookies
Going to a part-time MBA program requires juggling too many balls; keeping them all in air can be exhausting. Suppose you decided to go for the full-time program. But being a high-energy evening-MBA type of a person, full-time program did not challenge you enough so you opened a small business on the side.
You decided to run a cookie factory with your apartment-mate in your apartment. Baking cookies is simple: mix all the ingredients in a food processor, spoon out the cookie dough onto a tray; put the cookies into the oven; bake them; take the tray of cookies out of the oven; let the cookies cool; and, finally, take the cookies off the tray and carefully pack them in a box. You have all the necessary equipment: one food processor, lots of trays and spoons, and one oven. It is a small oven that will hold only one tray at a time.
You have timed the necessary physical operations. The first step is for you to wash out the mixing bowl from the previous batch, add all the ingredients, and mix them in the food processor. The mixing bowl can hold ingredients for up to 3 dozen cookies but currently you are using it to mix the dough for one dozen cookies at a time. You then dish up the cookies, one dozen at a time, onto a cookie tray. These activities take six minutes for the washing and mixing steps, regardless of how many cookies are being made in the batch. That is, it takes the same time for mixing the dough for one, two or three dozen cookies. However, dishing up the cookies onto the tray takes two minutes per tray. A tray can only hold one-dozen cookies.
The next step, performed by the roommate, is to put the tray with cookies in the oven and set the thermostat and timer, which takes about one minute. After setting the oven, the one-dozen cookies on the tray bake for next nine minutes. The oven needs no attention during the baking time of 9 minutes.
Your roommate also performs the last steps of the process by first removing the tray from the oven and putting it aside to cool for at least 5 minutes. Removing the cookies from the oven takes only a negligible amount of time but it must be done promptly. The one-dozen cookies are then carefully packed in a box by the roommate. The box is then stored in a shipping area and payment documents are attached to it. This ship/pay activity is performed by the roommate and is the last step in the process. It takes two minutes to pack each dozen and about one minute for the last ship/pay step
Here is a diagram showing the flow of the process:
Suppose the factory has been running for some time:
(1) Your chocolate-chip loving aunt walks in right at the moment you are starting a new one-dozen batch and asks you to make a special box for her. It does not take you any extra time to put in some extra chips. How long does she have to wait to get the box?
(2) How many boxes of one dozen cookies can be produced in an hour?
(3) Any suggestions for increasing the capacity of the process?