R S T

U V W

X Y Z

Each of the letters in the table above represents one of the numbers 1, 2, or 3, and each of these numbers occurs exactly once in each row and exactly once in each column. What is the value of r?

(1) v + z = 6

(2) s + t + u + x = 6

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

谢谢，为什么（1）对？？不明白。。。

条件一可以推出r＝3。理由如下：

若r不等于3，则r所在行，列必有等于3的项，此项（等于3）与v（3），z（3）处于同一行或同一列，与题意矛盾，所以r＝3

2) 也对呀。

for 1). V<=3,z<=3 => V+Z<=6, 而且只有V=Z=3时等号成立。这样R只能是3；

for 2).(S+T)+ (u + x ) = 6 同样=> S+T = 3， 所以R=3。