Equations

This topic has expert replies
Newbie | Next Rank: 10 Posts
Posts: 5
Joined: Sat Apr 18, 2015 6:11 pm

Equations

by rumi21 » Tue Jul 07, 2015 7:07 pm
Hello Everyone,

I need help with the below question. It seemed pretty simple to me and for me the answer is "EACH statement ALONE is sufficient".

Q-> Does q have a distinct value?

1) (2q-3)^2 = q^2
2) (12-q)^1/2 = 3


My thinking behind the answer is as statement 1) gives two different roots so q does not have a distinct value. And statement 2 gives one root so q have a distinct value.

But as per the solution only statement 2 is sufficient.

Please provide your valuable feedback.

Senior | Next Rank: 100 Posts
Posts: 52
Joined: Wed Jun 24, 2015 10:57 pm
Thanked: 3 times
Followed by:1 members

by mindful » Tue Jul 07, 2015 10:56 pm
Are you sure, that's the answer? My answer is the same as yours!
The roots of the first 1, 3. Roots of the second 3. Each alone does seem sufficient.
What are we missing?

Newbie | Next Rank: 10 Posts
Posts: 5
Joined: Sat Apr 18, 2015 6:11 pm

by rumi21 » Tue Jul 07, 2015 11:00 pm
Thanks for the reply. @mindful
Yes. That's what I am confused about. In the book which I was following the answer is different from ours.

GMAT/MBA Expert

User avatar
Elite Legendary Member
Posts: 10392
Joined: Sun Jun 23, 2013 6:38 pm
Location: Palo Alto, CA
Thanked: 2867 times
Followed by:511 members
GMAT Score:800

by [email protected] » Wed Jul 08, 2015 8:51 am
Hi rumi21,

What is the source of this question? I ask because this prompt is NOT something that you would see on the Official GMAT (and if you're using a source that is offering unrealistic material, then you would be better served working with a different resource).

The prompt should really ask: "What is the value of Q?" With this wording, Fact 1 would be insufficient (as Q could be two different values), while Fact 2 would be sufficient (as Q can be just one value).

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image

Newbie | Next Rank: 10 Posts
Posts: 5
Joined: Sat Apr 18, 2015 6:11 pm

by rumi21 » Wed Jul 08, 2015 9:39 pm
Thanks for the answer Rich. I was just exploring some questions on internet. And came across this question.
Can you please suggest some book for practicing DS questions other than the Official Guide.

Legendary Member
Posts: 518
Joined: Tue May 12, 2015 8:25 pm
Thanked: 10 times

by nikhilgmat31 » Mon Jul 13, 2015 11:27 pm
Answer is D

since the question is asking for "Does q have a distinct value? " It is YES/NO question.

It is not asking for value of q.

1) (2q-3)^2 = q^2 leads to 1 & 3 so NO. SUFFICIENT
2) (12-q)^1/2 = 3 leads to 3 so YES. SUFFICIENT.