Mr. Sho operates a news-stand and sells newspaper

- orders copies of the newspaper from the publisher at a cost of $4 per copy

- sells at a retailing price of $7

- The demand can be described with a normal distribution with mean 100 and standard deviation 12.

Questions:

How many copies should he order every day? (I got the answer of this part which is Critical fractile 0.4286, z=-0.18, Optimal Q*=97.84)

How much should Mr. Sho order if he wants to ensure a minimum service level of 70%?