请教一道经济学中的问题,希望得到解答,非常感谢:

If both average product (AP) and marginal product (MP) are equal to 4 when 10 workers are emplyed, what can we most likely conclude about AP and MP when 15 workers are emplyed?

A. AP=MP=5
B. AP=5 and MP=6
C. AP=4 and MP=6
D. AP=7 and MP=5

正确答案的解释:
D
For most production processes, as the quantity of labor increases, marginal product is initially grreater than average product. Then at some level of labor input, the two curves intersect. Then beyond this intersection, marginal product is less than average product. So, beyond AP=MP=4, MP must be less than AP. (Hint: drew the curves.)

虽然答案是D,但我认为AP与MP的曲线相交点的右边,AP和MP都是下降趋势,
因为MP呈下降趋势才会与AP相交,而下降的MP也会造成AP在相交点之右开始呈下降趋势.
所以我认为beyond AP=MP=4, 应该是MP<AP<4,
题目中显然没有符合的选项, 而D选项的MP,AP均>4.
究竟是题目不合理还是我的理解有错误呢? 忘高人解答,非常感谢.

[此贴子已经被作者于2007-4-22 19:20:23编辑过]

有人帮忙解答一下吗.

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You are quite correct with your reasoning - the question has an error in it and has been posted on the Schweser website: http://www.schweser.com/news/notes_updates.php?type=schweser

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