The daily demand for six-packs of Coke at Mr. Ds supermarket follows a normal distribution with mean 120 and standard deviation 30. Every Monday the Coke delivery driver delivers Coke to Mr. Ds. If Mr. Ds wants to have only a 1% chance of running out of Coke by the end of the week, how many should Mr. D order for the next week? Assume orders are placed on Sunday at midnight. Also assume that demands on different days are probabilistically independent.

Please do not copy the answer from the internet as I've already seen that.