[求助]明天考试，Prep中1道数学题求教！！！

Freehorser

1. If m and r are two numbers on a number line, what is the value of r?

(1) The distance between r and 0 is 3 times the distance between m and 0;

(2) 12 is halfway between m and r.

我选了C，但答案是E。哪位NN解答一下吧？谢谢！！

tuxiaoyangs

(1)不充分，r可以大于0，也可以小于0。

（2）单独也不充分，不知道m or r的具体值

1&2， 也不行，m>0, 3om=or,get the key: r=18; m<0, get the other key: r=36.

freedownload

护照没签名就自己签啊。我晕，你就是在考场签都可以啊!

Freehorser

thanks !!!!!!!!![em05]