35 Lindsay Hawkes sells discs that contain 25 software packages that perform a variety of financial functions typically used by business students. Depending on the quantity ordered, Lindsay offers the following price discounts:

ORDER QUANTITY PRICE 1 to 600 $10.00 601 to 1,100 $ 9.92 1,101 to 1,550 $ 9.86 1,551 and up $ 9.80 The annual demand is 3,000 units on average.
Lindsay’s setup cost to produce the discs is $350. She estimates holding costs to be 10%
of the price, or about $1 per unit per year. What is the optimal number of discs to produce at a time?