弱问TT GWD1-13

开始做GWD了,是先做GIGI13还是TT31?请指教！

象这种比较大小的题有捷径吗，我都比乱了

If x and y are positive, is 3x > 7y?

(1)     x > y + 4

(2)     -5x < -14y

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.

Answer: B

由（2）推出：5x>14y，好像不会很难的阿。

这样就能推出3X>7y?还是不很明白。条件1怎么分析呢？是用代入法吗？

If x and y are positive, is 3x > 7y?

(1)     x > y + 4

(2)     -5x < -14y