prep的答案给错了吗？？

hebeqiao

大家看看这道题：

In a certain bathtub, both the cold-water and the hot-water fixtures leak. The cold-water leak alone would fill an empty bucket in C hours, and the hot-water leak alone would fill the same bucket in H hours, where C<H, if both fixtures began to leak at the same time into the empty bucket at their repective constant rates and consequently it took T hours to fill the bucket, which of the following must bu true?

1, 0<T<H

2,C<T<H

3,C/2<T<H/2

Answer is 1 and 3, but why 3 is correct??? I'm almost sure that the answer is wrong.

chonheinrich

设C=2，H=3，则T=6/5

答案没错，LZ请细心。

hebeqiao

got it, Thanks!

zhangsr

t=c/(1+c/h)

c<h