请教三道prep数学题

mylittlebird · 发表于 2010-8-11 21:59:08

1 The number 75 can be written as the sum of the squares of 3 different positive integers. What is the sum of these 3 intergers?

A 17
B 16
C 15
D 14
E 13
Key is E。请问如何求解？谢谢！

2 If n is a positive integer and r is the reminder when (n-1)(n+1) is divided by 24, what is the value of r?
(1) n is not divisible by 2.
(2) n is not divisible by 3.
答案是C。请教求解方法。

3 In the xy-plane, does the line with equation y=3x+2 contain the point (r,s)?
(1) (3r+2-s)(4r+9-s)=0
(2) (4r-6-s)(3r+2-s)=0
答案为C。我选的是D，不是每个都能解出一对（r，s）吗？请大侠们帮忙指点，谢谢！

mylittlebird · 发表于 2010-8-12 22:11:42

顶一下。请大侠们帮忙啊，多谢啦。。。

请教三道prep数学题

所属分类: GMAT考试

正在浏览此版块的会员 ()