Quick Print Inc. uses plain paper for copying needs. Weekly demand for that paper follows a normal distribution with mean $100$ and standard deviation $50($measured in boxes$).$ Each week, a replenishment order is placed with its supplier and the order arrives one week later. All copying orders that cannot be satisfied immediately due to the lack of paper are backordered. Suppose that Quick Print decides to establish an order$-$up$-$to level of $300$ boxes for plain paper. At the start of this week, there are $200$ boxes in inventory and $60$ boxes on order. How much will Quick Print order this week?