x^4+y^4 > z^4? Data sufficiency problem

by **gphil** Mon Oct 29, 2007 5:14 pm

Could please somebody explain the solution of the problem? The correct answer is E) Statements 1 and 2 together are NOT suffisient. Thanks!

Is x^4+y^4 > z^4?

1) x^2+y^2 > Z^2
2) x+y > z

by **gphil** Mon Oct 29, 2007 8:51 pm

Sorry for this question. I found the explanation below.
Thanks!

by **RonPurewal** Tue Oct 30, 2007 5:05 am

by **pravsr** Thu Nov 08, 2007 1:48 pm

is b the right answer?

i think statement 2 is sufficient to answer. i plugged in a lot of values.

by **RonPurewal** Fri Nov 09, 2007 4:08 am

If you plugged in a lot of values for statement 2, then that probably means you didn't plug in the right KINDS of values. Since this problem doesn't place any restrictions on the numbers, you need to try positive, negative, and zero.

Anyway, here are two examples for statement (2):
* x = y = 1, z = 0. Then the answer to the prompt question is YES (1 + 1 > 0).
* x = y = 2, z = 3. Then the answer to the prompt question is NO (16 + 16 > 81).
So that's insufficient.