a. Determine which delivery alternative would be most economical for 80 boxes of parts. Each box costs $240 and annual holding cost is 30 percent of cost. Assume 365 days per year. Freight costs are:

Alternative	Freight Cost (for all 80 boxes)
Overnight	$360
Two-day	312
Six-day	216

Alternative (Click to select) Two-day Six-day Overnight

b. For what range of unit cost for a box would each delivery alternative be least costly? (Do not round intermediate calculations. Round the final answers to 2 decimal places.)

Overnight is cheapest if unit cost > $ . Two-day delivery is cheapest if $ < unit cost < $ . Six-day delivery is cheapest if unit cost < $ .