firm's materials requirement is $50,000$ units $($price Rs$\mathrm{.}4$ per unit$).$ The ordering cost per order is Rs$.20$ and the carrying cost is $12\mathrm{.}5\%.$ If the discount schedule given below applies to the firm, determine the most economical order quantity.Discount RateLot Sizenone$1-9991\%1000-19992\%2\mathrm{.}000-2,9993\%$