[求助]关于问题求解，不太理解答案何来……

For every positive enen interger n, the function h(n) is defined to be the product of all the even ingergers from 2 to n, inclusive. If P is the smallesting prime factor of h(100)+1 ,then p is ____

答案: more than 40

In a certain bathbub, both the cold water and the hot water fixtures leak. The clod-water 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 rates and consequently it took t hours to fill the bucket, which of the following must be true?

1. 0<t<h

2. c<th

3. c/2<t<h/2

答案:1&3

哪位nn能解释一下why么？

已经琢磨出第二天如何解，但是第一题就……

毛人offer help么？

t=1/(1/c+1/h)=ch/c+h

代入到c/2<t<h/2里面去验算一下就可以了。