Facilities planning

An order of 20 custom-designed castings has been received. Each casting costs $ 400 per scheduled castings. If the casting is good, it is then finished to specifications at an added cost of $ 250. Excess good castings are not finished but are recycled at value of $100. If the casting is not good, it is recycled at a value of $ 50. The customer is willing to pay $ 900 for 20 acceptable castings. Also, he has agreed to accept 21 to 25 castings at a price of $800. (a) Formulate the revenues function b) Calculate the profit when the lot quantity is 28 and number of good items = 23. Show calculations. Donu