D's Dairy is a company that distributes A2 beta-casein milk cartons from its local Distribution Center (DC) to its surrounding neighborhood region. They load the milk cartons each morning into their mini-vans and go around the region of 12 km by 20 km to deliver milk cartons to their customers. Their DC is located in the south-east corner. Consider the following information:

1) Each mini-vans can carry 25 milk cartons.

2) The cost to load each mini-van is $3.

3) The cost to stop, unload and deliver a single carton to each customer is $2. Assume each customer purchases only one carton per day.

4) The cost of driving a mini-van is $13 per km.

5) Number of customers = 84.

Using continuous approximation, estimate the number of mini-vans required by the company to deliver milk cartons in this region.