There is no missing value

For the following question, let X = the last 2 digits of your student ID number. The Nova Bookstore sells 2020 calendars. The single order for the calendars from the suppliers arrived in September 2019, and is offered for sale until July 2020. The demand for the calendars in the period from September to July follows a normal distribution with mean 500+X calendars, and standard deviation 120. The calendars cost OMR 2.000, and the bookstore sells them for OMR 3.000 each. a) If the bookstore throws out all unsold calendars at the end of July, how many calendars should be ordered? (4 marks) Number of calendars ordered = b) If the bookstore reduces the price of the calendars to OMR 0.500 at the end of July, and can sell all of the remaining calendars at this price, how many calendars should be ordered? (4 marks) Number of calendars ordered = c) What is the probability that the quantity of calendars ordered in part b) above will be sold before the end of July? (2 marks) Probability is =