A sandwich salesman wants to determine how many sandwiches to order from the supplier every day. Daily customer demand could be 20 (30% probability), 30 (20% probability), 40 (35% probability) or 50 (15% probability). The salesman buys the sandwiches for $1 and sells them for $2.50. Any sandwiches which are not sold have to be thrown away at the end of that day. What is the optimum level of sandwiches to order? ?20 ?30 ?40 ?50
please explain this question and let me know are these type of questions coming in exam