can you plz answer a to c? make sure to show all the step

The bus 101 class starts a new business in the student union. They plan to sell their new product which is guaranteed to give everyone an A on all their finals. The price they will sell it for is $100 and it costs them $70 per unit to make. If they cannot sell all the units before finals, they can resell them after the semester for only $20. a) Find the Cu (cost of underestimating). b) Find the Cs (cost of overestimating). c) P (Q*) or probability of the optimal order quantity = Cu / (Cu + Cs)