问题如下：
Healthy Co. is a factory which producing health care products. The long-run average total cost is $15 per unit and total output is 500 units. The manager plans to increase the total output to 600 units. After some calculation, it is expected that the long-run average total cost will increase to $18. Which of the following description about Healthy Co. is most appropriate?
选项：
A.Healthy Co. is experiencing the constant returns to scale.
B.Healthy Co. is experiencing the diseconomies of scale.
C.Healthy Co. is experiencing the economies of scale.
解释：
B is correct.
When the scale of the business increases (at 600/500-1=20%), the average unit costs increases (at 18/15-1=20%) as well. An upward-sloping long-run average total cost curve means diseconomies of scale.
考点：规模经济。
解析:产出上涨了600/500-1=20%，平均销售成本也上涨了18/15-1=20%
注意到平均单位成本的上涨就意味着企业运行在规模不经济的阶段。
单位成本都是33.3，500/15,600/18,单位成本不变不应该是规模经济吗
