2 Coffee and donuts at a certain coffee shop all the custom

2. Coffee and donuts - at a certain coffee shop, all the customers buy a cup of coffee some also buy a doughnut. The shop owner believes that the number of cups he sells each day is normally distributed with a mean of 320 cups and a standard deviation of 20 cups He also believes that the number of doughnuts he sells each day is independent of the coffee sales and is normally distributed with a mean of 150 doughnuts and a standard deviation of 12. (Exercise 59 from the book) a standard deviation of 12.

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