为什么算分母的时候不包括36

问题如下：

A company has an unsecured line of credit and needs to maintain its EBIT-to-interest coverage ratio greater than 2.0. Its EBIT is estimated to be between $36 million and $48million, with all values equally likely. If the forecasted interest charge for the year is $20million, the probability that EBIT/interest will be more than 2.0 is closest to:

选项：

A.

66.7%

B.

61.5%

C.

33.3%

解释：

The EBIT-to-interest ratio is equal to 2.0 when the EBIT is $40 million. Given that the values between $36 million and $48 million are equally likely, the probability of the ratio being equal to or less than 2.0 is 33.3% (= [$40 million – $36 million]/[$48 million – $36 million]). Consequently, the probability of the ratio being greater than 2.0 is 66.7% (i.e., 1 – Probability of the ratio being equal to or less than 2.0).