Continued from question $1)$ Suppose Quarks's Sheka supplier now offers quantity discount. If Quarks orders more than $20,000($including $20,000)$ packages in a single order, it will be charged a discounted price for all units ordered.

$$If the discount rate is $1\%,$ find the optimal order quantity and total annual cost including fixed ordering cost, variable ordering cost, and inventory holding cost. $(3$pt$)$

$$If the discount rate is $0\mathrm{.}1\%,$ find the optimal order quantity and total annual cost including fixed ordering cost, variable ordering cost, and inventory holding cost. $(3$pt$)$