再次请教PREP 上的数学题。谢谢大家

blueflower86

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.

 

这道题目选A。我认为为什么不可以选D啊。第二个也是可以推出来的啊

 

A fast company plans to build 4 new restaurants. If there are 12 items that satisfy the company’s criteria for location of new restaurants, how many different ways can the company select the 4 sites needed for new restaurant if the order of selection doesn’t matter?

这道题我认为是P（12，4）。可是答案为什么是495啊。

hellokelly

1. for 2) C could lie to the left of A
2 C124the order of selection doesn’t matter?