2 intesecting lines..

Question

Two intersecting lines form four angles. Are the lines perpendicular?

(1) Each of the angles is equal to exactly one of the other three angles.

(2) The sum of three angles does NOT equal to 270 degrees.

A) Statement (1) BY ITSELF is sufficient to answer the question, but statement (2) by itself is not.

B) Statement (2) BY ITSELF is sufficient to answer the question, but statement (1) by itself is not.

C) Statements (1) and (2) TAKEN TOGETHER are sufficient to answer the question, even though NEITHER statement BY ITSELF is sufficient.

D) Either statement BY ITSELF is sufficient to answer the question.

E) Statements (1) and (2) TAKEN TOGETHER are NOT sufficient to answer the question, meaning that further information would be needed to answer the question.

atlantic · Answer

Hi,

Not sure about what is the correct answer but I would bet on B.

Let me explain why.

(1) we get nothing at all. It only says that anyone of the angles has another one with the same degree, but not that all the angles are equal - which is necessary to say that the lines are perpendicular. INSUFF

(2) the lines are only perpendicular if all the angles are equal, being all 90º. Here it says that the sum of any three angles cannot be equal to 270º and therefore, angles are not 90º angles. SUFF.

Hope it helps. Do you have the OA.

BTW: it took me less than 2min.

albertrahul · Answer

I second Atlantic, my vote goes for B as well. What is OA?

durgesh79 · Answer

its D

statement 1 : Each of the angles is equal to exactly one of the other three angles.

if the lines were perpedicular, then each of the sangle would have been equal to all other 3 angles ... if t is known that each of the angle is equal to exactly one of the other three ... we can say that the lines are not perpendicular ...... ans we have to answer YES or NO .....

atlantic · Answer

Guess you're correct durgesh. Only if 'exactly' was replaced by 'at least' would (1) not be enough. I should read statements more carefully. Again this is one of the competences tested by GMAT.

shipra · Answer

OA is D....even i went fr B....i kind of agree wid atlantic...how is the first statement Sufficient?

albertrahul · Answer

Well first sentence tells us that each angle is equal to ONLY ONE other angle. This information is sufficient to answer question that is asked, "Are these two lines perpendicular?"
For two lines to be perpendicular each angle should equal other Three angles.

g_beatthegmat · Answer

(D).

Both are sufficient as durgesh79 mentioned above because of the following reasons -

i) Each of the angles is equal to exactly one of the other three angles.
If the lines were perpendicular to each other, all the angles would have been equal to 90 degrees. But the statement says each of the angles is equal to just ONE other angle, and that's obviously the corresponding vertical angles.

Hence sufficient.

ii) The sum of 3 angles is NOT 270.
If the lines were perpendicular, sum of any 3 angles would have been = 270.

Hence sufficient.

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