alltimeacheiver 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.

Material K cost "C" can be found out by calculating

C= (3*x+5*y)/10

Now the cost C will be close to Material A cost if x is more than y and vice versa

from St 1 we have y>4

For eg y=5, x=5 Cost of Material K will be $4/kg (in between price of Material A and Material B)

now if x=4,y=6 ,Cost of material K will be be $ 4.2/kg

if x=1,y=9 then Cost of material will be 4.8$ per kg

but if we take y=4 and x=6 we get cost of material K as $ 3.8 per kg less than $ 4 which would have been the price had both material A and B were added equally.

Therefore if x>y we should have price of Material K < $ 4kg

Hence St1 alone not sufficient as we can have x=y or x<y

St 2, The cost of the 10 kilograms of Material K is less than $40.[/quote]

Cost of Material per kg <$4 which meets our above requirement which means x>y

Therefore ans st B

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