Data Sufficiency

Question.1:

If x and y are positive, is x^3 > y

(1)square root of x >y
(2)x > y

Question.2:

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 ykilograms of material B, is x > y?

(1) y > 4
(2) The cost of the 10 kilograms of material K is less than $40.

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Quants-Master

1.E
2.B

Q1 E

Stmt 1

let x = 1/4, y = 1/8

sqrt(x) = 1/2 --> x > y,

x^3 = 1/64 not greater than y

let x = 9, y = 2

sqrt(x) = 3 --> x > y

x^3 = 729 > y

Not suff

stmt 2.

consider the same 2 cases above.
Not suff

combine 2 stmts.
the same 2 cases fit and hence together the statements are not suffecient.


Q2 B

total cost 3x + 5y

stmt 1
y>4, does not say anything about x

therefore y can be 4.1 to 9.9, and x can be 0.1 to 5.9.

not suffecient

stmt 2

3x + 5y < 40

x=5,y=5 gives sum as 40.
Y should always be less than X

B sueff