The question: A sell-out crowd of $42,200$ is expected at Cleveland's Jacobs Field for next Tuesday's game against the Baltimore Orioles, the last before a long road trip. The ballpark's concession manager is trying to decide how much food to have on hand. Looking at records from games played earlier in the season, she knows that, on the average, $38$% of all those in attendance will buy a hot dog. How large an order should she place if she wants to have no more that a $20$% chance of demand exceeding supply?
I know I need to use a normal distribution for this but I am having trouble figuring out what the specific parts are, for example, what is n?