answer must be in 100-200 words

Please help solve all... please Geliga Bhd. is a distributor of industrial product in Johor. Item A is one of the materials needed in the production process. Item A is consumed at a steady usage at 4000 units per annum. The costs of ordering item A are invariant with respect to order size. The ordering cost has been calculated at RM30 per order. Each order is checked by an employee engaged in using item A in production who earns RM5 per hour irrespective of his output. The employee generates a contribution of RM4 per hour when he not involved in material checks and the stock check takes 5 hours. Annual holding cost amount to RM15 per unit. Required: a. Calculate the optimal order size of item A. b. The supplier of item A has recently offered Geliga Bhd. a quantity discount of RM0.24 per unit on the current price of RM24, for all orders of 400 or more units of item A