Daily demand for fresh cauliflower in the ZZ-Warehouse store follows normal distribution with mean 100 cartons and s.d. 20 cartons. The ZZ-Warehouse buys at a cost of $50.00 per carton, sells it for $70.00 per carton. Unsold cartons are sold for $20.00 per carton. What is the optimal order quantity, using the single period model?