(30号考了,希望G友帮帮忙)求助: gwd7-3,

Material A costs $3 per kilogram, and material B costs $5 per kilogram.  If 10 kilograms of material K consists of x kilograms of material A and y kilograms of material B, is x > y?

(1)     y > 4

(2)     The cost of the 10 kilograms of material K is less than $40.

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: D (B)

觉得A是可以推出的,因为y=5,x=5,y大于5,x<y,所以不管怎么样,都是和题干的结论相反的.

希望同学帮帮忙,解答一下.

(1)可能x=y，也可能x>y，甚至x<y

(2)y<5,x+y=10,所以一定是x>y

嘿嘿，谢谢大家