Table 4 below shows the production of good X by a particular firm. Suppose that the wage rate of labour is $12 per hour, and that the cost of each machine is $20 per day regardless of the quantity of good X produced.

Table 4 Quantity of Quantity of Quantity of good X workers machines produced per hour 2 5 2 10 2 20 2 35 VOI AWN 2 55 2 70 N 80