BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Please check this DS question out!!

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 209
Joined: Thu Jan 12, 2012 12:59 pm

Please check this DS question out!!

by dddanny2006 » Tue Aug 27, 2013 4:50 am
Hello people,

Needed your opinion on this
Its a simple question.
If a>0,b>0 and 2c=sqrt(a/b) ,what is the value of b

1.a=8 and c=2
2.(c^2/a)=1/2 (Its c square by a equals half)

The answer is D

Now my question is what if they had not given a>0 and b>0

Does it impact the question?

Or does the answer remain the same in that case too??


Please share your opinion on this.

Thanks
Top
Source: — Data Sufficiency |
User avatar
MBA Admissions Consultant
Posts: 2279
Joined: Fri Nov 11, 2011 7:51 am
Location: New York
Thanked: 660 times
Followed by:266 members
GMAT Score:770

by Jim@StratusPrep » Tue Aug 27, 2013 8:24 am
Wouldn't matter in the context of the GMAT because you can't take the sqrt of a negative number. That is all they are getting across.
GMAT Answers provides a world class adaptive learning platform.
-- Push button course navigation to simplify planning
-- Daily assignments to fit your exam timeline
-- Organized review that is tailored based on your abiility
-- 1,000s of unique GMAT questions
-- 100s of handwritten 'digital flip books' for OG questions
-- 100% Free Trial and less than $20 per month after.
-- Free GMAT Quantitative Review

Image
Top

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] » Tue Aug 27, 2013 11:54 am
Hi dddanny2006,

I'm going to elaborate on what Jim offered regarding certain math subjects on the GMAT. The Quant section of the GMAT comes with many restrictions, which is why the questions are so specifically worded.

For example, a question that refers to x/y will also have to state that y CANNOT EQUAL 0, because dividing by 0 (otherwise known as "undefined numbers" or "infinities") is not a subject that's tested on the GMAT.

To be more specific, you will never be asked to do Calculus, Trigonometry, or Algebra II. In this question, you won't be asked to take the square root of a negative number because THAT is an Algebra II subject (so the limitations on a and b had to be included in the instructions).

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 358
Joined: Thu Apr 18, 2013 9:46 am
Location: Jeddah, Saudi Arabia
Thanked: 42 times
Followed by:7 members
GMAT Score:730

by faraz_jeddah » Wed Aug 28, 2013 6:41 am
[email protected] wrote:Hi dddanny2006,

I'm going to elaborate on what Jim offered regarding certain math subjects on the GMAT. The Quant section of the GMAT comes with many restrictions, which is why the questions are so specifically worded.

For example, a question that refers to x/y will also have to state that y CANNOT EQUAL 0, because dividing by 0 (otherwise known as "undefined numbers" or "infinities") is not a subject that's tested on the GMAT.

To be more specific, you will never be asked to do Calculus, Trigonometry, or Algebra II. In this question, you won't be asked to take the square root of a negative number because THAT is an Algebra II subject (so the limitations on a and b had to be included in the instructions).

GMAT assassins aren't born, they're made,
Rich
Thanks Rich for a detailed explanation.

There is another rule regarding square roots. Can you confirm the rule below

x^2 = 4
x can be 2 or -2

but if
x = sq.rt 4
then x can only be 2.
A good question also deserves a Thanks.

Messenger Boy: The Thesselonian you're fighting... he's the biggest man i've ever seen. I wouldn't want to fight him.
Achilles: That's why no-one will remember your name.
Top

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 Aug 28, 2013 12:16 pm
Hi faraz_jeddah,

You are correct. On the GMAT, if you start with....

x^2 = 25, then there are TWO answers: +5 and -5

But if you start with...

squareroot(25), then there is JUST ONE answer: +5

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image
Top
Post new topic Post Reply
• Page 1 of 1