Hi LUANDATO,

This Geometry question is based on a couple of standard line and circle 'rules' that you'll need to know for Test Day:

1) A circle has 360 degrees
2) Each line has 180 degrees
3) Opposite angles in a pair of 'criss-crossing' lines are equal

Based on the drawing, we can see that two lines cross through the center of a circle forming a 120 degree angle. By extension, the angle 'across' from that angle is also 120 degrees and the other two angles are both 60 degrees. Thus, Y=60

Each of the two "Y regions" represents 60/360 = 1/6 of the circle, so the sum of those 2 regions = 1/6 + 1/6 = 2/6 = 1/3 of the circle.

Final Answer: C

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

BTGmoderatorLU wrote:

The two regions marked with the letter Y comprise what fraction of the circle above with the center O?

A) 1.
B) 1/2.
C) 1/3.
D) 1/6.
E) 1/12.

The OA is C.

I'm really confused with this PS question. Please, can any expert assist me with it? Thanks in advanced.

Since the angles of the two Y regions sum to 120, those regions are 120/360 or 1/3 of the circle.

Answer: C