The America Dog and Cat Hotel is a pet hotel located in Las Vegas. Assume that in March, when dog-days (occupancy) were at an annual low of 1,000, the average cost per dog-day was $14. In July, when dog-days were at a capacity level of 4,000, the average cost per dog-day was $8.

(b) Determine the average cost per dog-day at an annual volume of 24,000 dog-days.