OG Ed.11 DS # 117

This topic has expert replies
Junior | Next Rank: 30 Posts
Posts: 19
Joined: Sun Nov 30, 2008 1:44 pm
Thanked: 2 times

OG Ed.11 DS # 117

by ifairo » Wed Jan 14, 2009 10:26 am
Please help me with your answer. If this problem has already been posted, then please refer me to the link.

Thanks.[/img]
Attachments
OG - DS 117.jpg
Source: — Data Sufficiency |

Junior | Next Rank: 30 Posts
Posts: 28
Joined: Sun Nov 02, 2008 12:35 pm
Thanked: 7 times

by sachinkr » Thu Jan 15, 2009 12:02 pm
As per question, Angle BDC = Angle BCD = 2x, therefore BC = BD.

Statement 1: AD = 6,
Angle ADB = 180-2x , so sum of Angle BAD and Angle ABD = 2x, but we cannot assume these two angles to be equal. So AD may not be equal BC. Therefore this statement is insufficient.

Statement 2: x=36, just knowing the angle would not help in determining the length of any side in this question. therefore insufficient.

Even with both the statements, we cannot get the length of BC.
Therefore (E). what is the OA?

Junior | Next Rank: 30 Posts
Posts: 19
Joined: Sun Nov 30, 2008 1:44 pm
Thanked: 2 times

OG Ed.11 DS # 117

by ifairo » Thu Jan 15, 2009 6:31 pm
I am not convinced why A should be right. If you guys believe this is, indeed, a right answer, then please explain.

Regards.
Attachments
OG - DS 117 - Ans.jpg

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

Re: OG Ed.11 DS # 117

by Brent@GMATPrepNow » Thu Jan 15, 2009 8:03 pm
ifairo wrote:Please help me with your answer. If this problem has already been posted, then please refer me to the link.

Thanks.[/img]
I agree, the answer here must be E.
We could take point A and move it either left or right. Doing so would still allow triangle BDC to remain an isosceles triangle with angles 2x, 2x and 180-4x. However, moving point A around, would ruin any chances that triangle ADB is the isosceles triangle that the solution seems to suggest.
Brent Hanneson - Creator of GMATPrepNow.com
Image

User avatar
Legendary Member
Posts: 2134
Joined: Mon Oct 20, 2008 11:26 pm
Thanked: 237 times
Followed by:25 members
GMAT Score:730

by logitech » Thu Jan 15, 2009 8:17 pm
Question is not complete. In the original question there is more info! :idea:
LGTCH
---------------------
"DON'T LET ANYONE STEAL YOUR DREAM!"

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 2623
Joined: Mon Jun 02, 2008 3:17 am
Location: Montreal
Thanked: 1090 times
Followed by:355 members
GMAT Score:780

by Ian Stewart » Thu Jan 15, 2009 11:00 pm
logitech wrote:Question is not complete. In the original question there is more info! :idea:
Exactly; in the original version of the question, angle DAB is labeled in the diagram; it measures x degrees. Then the answer is A. With the diagram in the original post, as pointed out above, the answer is clearly E.
For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com

ianstewartgmat.com