| Suppose that each firm that operates in an industry has a total cost curve given by TC = 7,000 + 50Q. In this industry, the lowest average total cost of producing 1,000 units of output occurs when: | 
  |  |    |  | four firms each produce 250 units of output. |   |  | ten firms each produce 100 units of output. |   |  | one firm produces all 1,000 units of output. |   |  | two firms each produce 500 units of output. |  | 
  
       | Suppose that each firm that operates in an industry has a total  cost curve given by TC = 7,000 + 50Q. In this  industry, the lowest average total cost of producing 1,000 units of  output occurs when: | 
    |  |       |  | four firms each produce 250 units of output. |    |  | ten firms each produce 100 units of output. |    |  | one firm produces all 1,000 units of output. |    |  | two firms each produce 500 units of output. |  | 
    
Average total cost=Total cost/Q
 ATC=7000/Q+50
 Hence ATC is lowest when only one firm produces 1000 units.