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27 Jan 2015, 07:40
Kudos
Bookmarks
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
45%
(medium)
Question Stats:
67% (02:12) correct
33%
(02:05)
wrong
based on 248
sessions
History
Date
Time
Result
Not Attempted Yet
Arc XYZ lies on a circle centered at O. Is a < 55?
(1) Angle ZOY = 35
(2) Angle XOY = 75
Kudos for a correct solution.
Attachment:
Q14_1.png [ 21.9 KiB | Viewed 8516 times ]
Pure algebraic questions like this one are no longer part of the GMAT Data Sufficiency syllabus.
For relevant Data Sufficiency questions, please check the Data Sufficiency forum:
Data Sufficiency Forum
Data Sufficiency Forum
27 Jan 2015, 09:35
Kudos
Bookmarks
ans C...
both statements are required to get angle zox which is equal to 2a..
both statements are required to get angle zox which is equal to 2a..
02 Feb 2015, 02:39
Kudos
Bookmarks
Bunuel
VERITAS PREP OFFICIAL SOLUTION:
The correct response is (C).
If we draw a radius from O to Y, we can fill in the two given values: ZOY = 35, and XOY = 75. OX and OZ are both radii of the same circle, so their opposite angles must be equal. We can use this information to solve for angle XYZ, and in term find the value for a.
To do the math, here’s how it would look:
Attachment:
Q14_2.png [ 24.07 KiB | Viewed 7606 times ]
180 = 35 + OYZ + OZY
145/2 = 72.5 = OYZ = OZY
180 = 75 + OXY + OYX
105/2 = 52.5 = OXY + OYX
Angle XYZ = 72.5 + 52.5 = 125
Angle a = 180 – 125
Angle a = 55
The answer to the question would always be “no.”
If you chose (A), this would allow us to solve for XYO, but we’d also need angle OYZ to find a.
If you chose (B), this would allow us to find OYZ, but we’d also need to know angle XOY to find angle XYO.
If you chose (D), both pieces of information are important, but neither is independently sufficient.
If you chose (E), you may have missed that XO = OY = OZ, since all radii in a circle must be equal, as well as the fact that angles opposite equal sides are also equal.
