Based on the plot of discrete probability, it can be seen that the distribution is symmetrical and the peak occurs at the stock of 30. If there is a sale of less than 30 such as 20 or 25, the seller is at a loss. Similarly, if the demand is above 30 such as 35 or 40, the seller is also at a loss. Therefore, there is approximately 2 sales to be lost each day based on the decision made by the seller.
No if it was, the football would keep going up forever and keep going up faster as it was released physics and common sense tells us that there is air resistance to slow the rise of the football
