Hi Sri,

This DS question will likely be easier to solve if you try to visualize what it asks for.

We're told that we're dealing with a box that has dimensions L, W and H. We're asked if it will fit through a 4 ft x 8 ft door? This is a YES/NO question.

The key aspect to this question is that the box can go through the door in any orientation.

Fact 1: L + W + H < 12

Let's TEST Values
L = 1, W = 1, L = 1
This box will clearly fit through the door, so the answer is YES.

L = 5, W = 5, L = 1
This box will fit through the door IF you turn it sideways, so the answer is YES.

L = 3.9, W = 3.9, L = 3.9
This box will fit through the door, so the answer is YES

Since the total has to be less than 12, there's no way to make the box "too big" to fit through the door.
Fact 1 is SUFFICIENT

Fact 2: L^2 + W^2 + H^2 < 256

L = 1, W = 1, H = 1
The answer to the question is YES.

L = 4.1, W = 4.1, H = 4.1
This box will NOT fit through the door, so the answer is NO
Fact 2 is INSUFFICIENT

Final Answer: A

GMAT assassins aren't born, they're made,
Rich