Can any one help me on part(c) of the following question. I did part(a),(b). Answer for (c) is 8days.
Q) A marina hires out boats on a daily basis. The mean number boats hired per day is 15. Using the normal approximation for a Poisson distribution find for a period of 100 days.
(a) How often 5 or less boats are hired
(b) How often exactly 10 boats are hired
(c) On how many days they will have to turn customers away if the marina owns 20 boats.
Yes, I did (a) & (b) just the way you've explained.(Cool)