Carrie Construction (CC) is a company specializing in building airport runways and major highways. As a part of its business, it receives supplies of aggregate (stone, sand, gravel, and so on) from two suppliers: Austin Aggregate and Granger Materials. The CC purchasing department has a preference for buying from Granger based on price but occasionally has to order from Austin when Granger cannot fill the order.

Carrie Construction has recently had problems with the quality and the timeliness of deliveries. When a supplier delivers a load to CC, it goes through an initial inspection to assure it meets specification. If the load fails the initial inspection, it goes through a secondary inspection to determine the exact issue. Almost always, the issue can be resolved and the load can be used. The initial inspection costs $3,240 per load. A secondary inspection, which is more thorough, costs $16,200 per load. If a delivery is delayed, Carrie has to hire temporary workers or pay overtime to some employees. The average cost of a delayed load is $6,480.

The following are summary statistics from last year's purchases from the two suppliers:

	Granger Materials	Austin Aggregate
Number of loads	648	214
Average tons per load	5,400	10,000
Average price per ton	$ 7.20	$ 8.00
Number of initial inspections passed	482	189
Number of delayed deliveries	152	31

Required:

Calculate the effective cost of a ton of aggregate from the two suppliers, assuming that last year's experience is representative.

Note: Round "Average effective cost per ton" answers to 2 decimal places.