The firm manufactures photocopying machines and the production plant requires $4197$ ?rollers every year. The supplier claims OMR $19\mathrm{.}8$ ?for ordering each time and each roller cost OMR $46\mathrm{.}4.$ ?The inventory carrying cost is estimated to be $34\mathrm{.}75\%$ ?of purchase cost. Calculate:inventory costs, economic, ordering quantity,optimum order interval in days