I hope the answer including the Formula , without using the Excel

a) Suppose Adam wants to buy shirts to sell in his neighborhood clothing shop. He can buy the shirts for RM10 each from a local factory and sell them in his shop for RM20. He estimates that he will sell 1,200 shirts per year. Originally, Adam planned to buy 100 shirts per month for a total of 1,200 shirts annually. What he hadn't planned on, though, is the factory charging him an additional RM150 setup cost every time he makes an order. At one order per month, this would add RM1,800 to the cost of the shirts. Adam then considers buying all 1,200 shirts upfront for a one-time RM150 setup fee, which saves him RM1,650. The problem now is Adam does not have enough space in his shop to store the extra shirts. He could rent storage space but this is also expensive, in the region of RM1.50 per shirt, per year. What's the optimal number of shirts that Adam should order at any one time to minimize both storage and production setup costs? (6 marks)