请问GWD的5套-3题的答案？

linlin2008

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

(1)y>4

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

看到的答案都不一样呢？到底是什么呢？

himba

我选B

(1)x=5,y=5 ;x=4,y=6......所以不充分

(2) 3x+5y<40

x+y=10

=> y<5 (因为当y>=5时,x=10-y<=5, 3x+5y>=40) ＝> x>y 故充分