The Central Valve Company sells industrial valves and fluid control devices. One of Central's most popular valves is the Western, which has an annual demand of 30,720 units. The price of each valve is $96, the inventory carrying cost is $2, and the ordering cost is $120 per order.
What is the optimal number of days between any two consecutive orders assuming 320 working days? Specify as a whole number by rounding the final calculation. Do not round the constituent calculations.