Calculate the average investment in inventory for each of the following situations. Assume a 365-day year.

a. The firm's annual sales were $18 million, its gross profit margin was 32 percent, and its average age of inventory is 45 days.

b. The firm's annual sales were $325 million, its cost of goods sold are 80 percent of sales, and it turns its inventory 10 times per year.

c. The firm's annual cost of goods sold total $120 million, and it turns its inventory about every 70 days.