COC的公式是什么？上课和讲义没有啊

问题如下：

Consider two projects, X and Y, with the same initial investment of $1,000. Which of the following statements is least correct?

选项：

If the Project Y's IRR equals to its required rate of return, then Y's NPV will be zero.

If the Project X's NPV=-$25, its IRR can still be positive.

If the Project Y's IRR=9%, its cost of capital=10%, then Y's NPV can still be positive.

解释：

C is correct.

Project Y's IRR is smaller than its cost of capital, in this case, Y's NPV must be negative.