PREP2数学题三道！马上就要考了想不明白

215.

On the number line, the distance between point A and point C is 5 and the distance between point B and point C is 20.  Does point C lie between point A and point B ?

(1)  The distance between point A and point B is 25.

(2)  Point A lies to the left of point B.

这个题答案选A，我怎么也想不明白B为什么不对呢？

(1) 10^d is a factor of f.

(2) d > 6

这个题答案是C，30！算出来是有6个0吧，d>6的话能成立么？

1.只知道A在B的左边不行，因为C也可以在A的左边，这时候AB间距15，C不在ab之间

2.我想lz一定是这么算的，10，20，30，12*15，22*25，2*5一共6个0，但是如果是25*24的话会有2个0，所30！石有7个0的

3.问的是additional amount，所以应该是x/(T-s)-x/T

谢谢　愁予　哥哥和LS　姐姐的回答哦～

明白了～

哪位能帮忙把第56题解释一下啊，我看不懂题目，谢谢了

To celebrate a colleague's retirement, the T coworkers in an office agreed to share equally the cost of a catered lunch.  If the lunch costs a total of x dollars and S of the coworkers fail to pay their share, which of the following represents the additional amount, in dollars, that each of the remaining coworkers would have to contribute so that the cost of the lunch is completely paid?

这个题答案是　SX/T(T-S)，　

为庆祝一个同事退休

T个员工开庆祝会，平摊费用x，s个人没有掏钱，其他人要分担这s个人的钱

问的是剩下来的这些人应该出多少钱才能够分担这s个人的钱

之前的是x/t,之后的是x/(t-s)

所以结果是是x/(t-s)-x/t