[email protected] wrote:Hi phanikpk,

In DS questions, you have to be suspicious of any drawings that are included (because sometimes pictures are not drawn to scale).

In this prompt, the language states the "present location" of a "sweeping beam" (the radius) as it moves clockwise around the circle. The question asks what quadrant of the graph the beam will be in in 30 seconds.

To answer this question, it looks like we'll need to know the starting position of the beam AND its rate of movement.

From the drawing and the wording, we know that the beam is currently in Quadrant I, but we don't know exactly where.

Fact 1: Every 30 seconds, the beam moves 3.69 degrees.

Depending on where the beam actually begins, it might still be in Quadrant I in 30 seconds.
If the beam starts really close to the X-axis though, it might move into Quadrant 4 in 30 seconds.
Fact 1 is INSUFFICIENT

Fact 2: R = 40

This tells us the angle that the beam is from the X-axis. However, without knowing what rate the beam is moving, it could be in any of the 4 Quadrants in 30 seconds.
Fact 2 is INSUFFICIENT

Combined,
We know that the beam is 40 degrees off of the X-axis.
We know that the beam moves 3.69 degrees clockwise every 30 seconds.

So...in 30 seconds, the beam will be 36.31 degrees off of the X-axis and it will be in Quadrant I
Combined, SUFFICIENT

Final Answer: C

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