EIs

x^4 + y^4 > z^4(1)

x^2 + y^2 > z^2(2)

x + y > zIt is obviously that x=10000, y=10000, z=1 satisfies both conditions and answer is "true".

So, I will try to construct example that satisfies both condition but answer is "false"

1. let x=y and z=1 for simplicity.

2. we need x<1 because

x^n will decrease when the power increases.

consider the fist condition:

2*x^2>1 -->

x>\sqrt{0.5} \approx 0.73. try x=0.8 (it satisfies both conditions):

2*0.8^4 = 2*0.64^2 < 2*0.7^2 < 2*0.49 < 1 bingo!

Here, I've tried to clarify my logic (for myself also

) when I construct examples.....just exercise

_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame