Farmfresh sells $750$units per month of watermelon. The unit cost of a watermelon to the store is rs $11$and the cost of placing an order is Rs$\mathrm{.}64.$Farmfresh uses an inventory carrying charge of $15\%$per year. Determine the optimal order quantity $,$order frequnecy and the annual cost of inventory management. If through automation of the purchasing process, the order cost can be cut to upto $28.$ what will be the new ecnomic order quantity, order frequnecy and and annual inventory managemnt cost explain these results