help! GWD 5-3

linxi8389

Q3:

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.

I chose c. why the key is B, please help me to solve it.

linxi8389

I got it , it seems that I made a simple mistake

dingding

I am still confused ? Can any body help me out? How can B

shisoblue

X+Y=10

3X+5Y<40  当 Y=5  X=5时  3X+5Y=40

所以 要Y<5  3X+5Y<40成立

又因为X+Y=10  所以 X>Y

mba06

I think this question should choose D. Since for A, y > 4, it means y >=5. Then x > y is false. It also explains the question. So D should be the right choice.

Can anyone verify?

mba06

never mind. y does not have to be integer. So B is the right answer. My fault.