Q24:

In the xy-plane, the line k passes through the origin and through the point (a, b), where ab ≠ 0.  Is b positive?

(1)   The slope of line k is negative.

(2)   a < b

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.

答案选C，是否B更合适？

因为根据题意可看出，只要在满足条件（2）（a<b，即x<y）的情况下，就能看出,(a,b)只能在坐标轴第一象限，即y>0，即b>0

(1)   The slope of line k is negative. 条件1告诉你这条直线过第二四象限

(2)   a < b         

条件2告诉你那个点在第二象限（在条件1基础上），而第二象限上的点纵坐标大于0，也就是b>0，故选C