If x

Question

If x < y, is x^4 < y^4 ? (1) y > 0 (2) x > 0 Kudos for a correct solution .

Skywalker18 · Answer

x x- y<0 x^{4} < y^{4} => x^{4} - y^{4} <0 =>( x^{2} + y^{2} )(x+y)(x-y)<0 ( x^{2} + y^{2} ) will be always positive and (x-y) is negative so the sign of inequality will depend on the sign of (x+y) 1. y>0 (x+y) can be positive or negative depending on x Not sufficient 2. x>0 =>x+y> 0 ( since x

mvictor · Answer

1 insufficient. x might be negative, and absolute value of x might be greater than y -> in this case, x^4 > y^4
2. x>0 -> this means that y is bigger than x, and absolute value of y is bigger than absolute value of x. regardless if it's a decimal or integer.
B is the answer.

HKD1710 · Answer

Given - x < y

1) y > 0, x can be negative or positive both for x < y to be true.
if x = -ve say x = -2 and y = 1 then x^4 > y^4
if x = +ve say x = 1 and y = 2 then x^4 < y^4

Insufficient.

2) x > 0, in this case y has to be +ve for x < y to be true.
if x = +ve say x = 1 and y = 2 then x^4 < y^4

sufficient.

B is the right choice.

musunna · Answer

Statement 1 says y > 0 and from stimulus we know x < y. So, if the value of x goes into negative the result (whether x^4 < y^4 ?) may flip as the power on x is even. NOT sufficient Statement 2 says x > 0, So, y > 0 too as y is greater than x. So, x^4 < y^4 . Sufficient. So Option (B) wins.

padman777 · Answer

we can breakdown original condition as
x2-y2<0
i.e. (x-y)(x+y)<0
but we know x<y
i.e.x-y<0
so x+y>0 --- this the original question

1. gives y>0
and y>x
this gives nothing about x+y so not suff

2. gives x>0
but y>x
so y>x>0 i.e. x and y are both positive
so x+y >0.. satisfies the original condition

ANS :B

If x < y, is x^4 < y^4 ?

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