GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 09 Dec 2018, 20:18

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel
Events & Promotions in December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
  • Free GMAT Algebra Webinar

     December 09, 2018

     December 09, 2018

     07:00 AM PST

     09:00 AM PST

    Attend this Free Algebra Webinar and learn how to master Inequalities and Absolute Value problems on GMAT.
  • Free lesson on number properties

     December 10, 2018

     December 10, 2018

     10:00 PM PST

     11:00 PM PST

    Practice the one most important Quant section - Integer properties, and rapidly improve your skills.

If c is a constant and x is a variable, what is the value of c in the

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Intern
Intern
avatar
B
Joined: 21 Feb 2018
Posts: 23
If c is a constant and x is a variable, what is the value of c in the  [#permalink]

Show Tags

New post 20 Jul 2018, 07:57
3
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

86% (00:50) correct 14% (01:44) wrong based on 51 sessions

HideShow timer Statistics

If c is a constant and x is a variable, what is the value of c in the equation x^2 +24x +c= 0?
1. The equation x^2+ 24x+ c= 0 has exactly one distinct solution.
2. 2. C is less than or equal to 144
Answer is A
Manager
Manager
avatar
G
Joined: 09 Jun 2014
Posts: 213
Location: India
Concentration: General Management, Operations
Schools: Tuck '19
Premium Member Reviews Badge
Re: If c is a constant and x is a variable, what is the value of c in the  [#permalink]

Show Tags

New post 20 Jul 2018, 08:30
1
My approach is as follows .

Let each root of the above quadratic equation be a.
Therefore ,sum of roots = 2a=-24/1..this implies a=-12

Now product of roots is a*a =C

We know a so we can get C wgich is equal to a^2

Statement 2: clearly insufficient

We know disriminant is always >=0
B^2 -4ac >=0

Therefore

576-4ac >=0
C<149

Many solution possible

So clearly A is the right answer .

Press Kudos if it helps !!

Posted from my mobile device
Intern
Intern
avatar
B
Joined: 21 Feb 2018
Posts: 23
If c is a constant and x is a variable, what is the value of c in the  [#permalink]

Show Tags

New post 22 Jul 2018, 13:48
If c is a constant and x is a variable, what is the value of c in the equation x^2 +24x +c= 0?
1. The equation x^2+ 24x+ c= 0 has exactly one distinct solution.
2. 2. C is less than or equal to 144
Director
Director
User avatar
P
Status: Learning stage
Joined: 01 Oct 2017
Posts: 931
WE: Supply Chain Management (Energy and Utilities)
Premium Member
Re: If c is a constant and x is a variable, what is the value of c in the  [#permalink]

Show Tags

New post 22 Jul 2018, 15:58
1
franteraoka wrote:
If c is a constant and x is a variable, what is the value of c in the equation x^2 +24x +c= 0?
1. The equation x^2+ 24x+ c= 0 has exactly one distinct solution.
2. c is less than or equal to 144


Question stem:- c=?

Statemement-1:- The equation x^2+ 24x+ c= 0 has exactly one distinct solution.
For a quadratic equation of the form, \(ax^2+bx+c=0\) to have an unique or one distinct solution, we have Discriminant is Zero or \(b^2-4ac-0\)

So, we have \(Discriminant={24}^2-4*1*c=0\)
So, the value of 'c' can be determined. (No need to solve the equation)
Sufficient.

Statement-2:- \(c\leq{144}\)

The value of 'c' can be any number with the above constraint.

Insufficient.

Ans. (A)
_________________

Regards,

PKN

Rise above the storm, you will find the sunshine

Manager
Manager
User avatar
S
Joined: 19 Nov 2017
Posts: 174
Location: India
Schools: ISB
GMAT 1: 670 Q49 V32
GPA: 4
Re: If c is a constant and x is a variable, what is the value of c in the  [#permalink]

Show Tags

New post 22 Jul 2018, 18:20
1
To split the middle term in an equation so that there is only 1 unique solution,
\(ax + by + c = 0\)

\(b\) should be splitted as \((\frac{b}{2})y + (\frac{b}{2})y\)
So c would be equal to \((\frac{b}{2})^2\)

Here \(b = 24\)
\((\frac{b}{2}) = 12\)
\(c = 12^2 = 144\)

Therefore, A is sufficient.
_________________

Regards,

Vaibhav



Sky is the limit. 800 is the limit.

~GMAC

Director
Director
User avatar
D
Joined: 27 May 2012
Posts: 627
Premium Member
Re: If c is a constant and x is a variable, what is the value of c in the  [#permalink]

Show Tags

New post 19 Aug 2018, 07:30
franteraoka wrote:
If c is a constant and x is a variable, what is the value of c in the equation x^2 +24x +c= 0?
1. The equation x^2+ 24x+ c= 0 has exactly one distinct solution.
2. 2. C is less than or equal to 144
Answer is A


Dear Moderator,

Came across this question, while doing DS section of Algebra, seems as though by mistake OA is visible out side the spoiler , making it futile for us to put effort into solving it. Hope you will look into this . Thank you.
_________________

- Stne

Manager
Manager
User avatar
G
Joined: 10 May 2018
Posts: 126
Concentration: Finance, Sustainability
Re: If c is a constant and x is a variable, what is the value of c in the  [#permalink]

Show Tags

New post 19 Aug 2018, 07:55
Classic Quadratic Equation Question!
I don't see these that often, nice question.
franteraoka wrote:
If c is a constant and x is a variable, what is the value of c in the equation x^2 +24x +c= 0?
1. The equation x^2+ 24x+ c= 0 has exactly one distinct solution.
2. 2. C is less than or equal to 144
Answer is A

_________________

Stuck in the 600-700 score bracket? I welcome you to read my four-step course of action to a modest score.
I also invite you to critique and help me find flaws in my modus operandi. Thanks!

GMAT Club Bot
Re: If c is a constant and x is a variable, what is the value of c in the &nbs [#permalink] 19 Aug 2018, 07:55
Display posts from previous: Sort by

If c is a constant and x is a variable, what is the value of c in the

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.