IMO C

There are 2 ways to do this.

1. Draw a graph for the eqn y=-x+1 and color in the required area. On doing so you'll see that statements 1 and 2 are not sufficient on their own. OTHH combining statements 1 and 2 regardless of the values of x and y, the eqn holds true.


2. Sub in values .. this can be tricky as which values will you choose? Regardless it's possible to show that either statement is insufficient by choosing large -ve and positive values for the x or y depending on what is given in the statement.

Got it. Thanks a ton.
OA is E.

Can you shed some light on the below problem. Inequalities seem to be a pain area for me.

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

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

According to me (1) should be sufficient since if we square (1), we get x^4 + y^4 + 2.x^2.y^2 > z^4
which implies that z^4 > x^4 + y^4 since 2.x^2.y^2 will always be positive.

Please let me know if there is an easy way to tackle inequality problems.