gluon wrote:

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.

S1:

For some reason, maybe its burn out, I can't see why S1 is insuff.

if y>4 then Y must be y>=5 (Assuming X and Y must be integers).

X+Y=10

If Y=5. Then X is not greater than 5 b/c 5+5=10 5not greater than 5.

So. NO

If Y =6 X is not greater than Y... Again NO. However, if we are allowed to say X and Y can be mixed numbers (4.5, 4.6, etc...) then S1 IS insuff.

S2:

3(x)+5(y)<40. So again assuming these must be integers the number 3(x)+5(y) <=to 38. Can't be 39 b/c 3(x)+5(y) (assuming x and y are integers) will never add up to 39 because X+Y must equal 10.

So in this case 3*6+5*4 = 38 X>Y Yes.

Now try to maximize Y w/o exceeding 39.

3(5) +5(5) = too big (15+25=40)

3(4) +5(6) = too big (12+30=42)

3(3) +5(7) = too big (9+35=44)

3(2) +5(8) = too big (6+40 =46) Y must be less than 5 so B is suff.

I say D for this one assuming X and Y have to be integers.

Please let me know about 1. I am a bit braindead right now.

Also 1 last thing. I thougt the statements werent suppose to contradict each other.

S1: y>4? S2: y must be 4 or less???