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

 It is currently 06 Dec 2019, 10:59 ### 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

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.  # Find the arithmetic mean of all roots of the following equation

Author Message
TAGS:

### Hide Tags

Intern  Joined: 05 Apr 2011
Posts: 10
Find the arithmetic mean of all roots of the following equation  [#permalink]

### Show Tags

3
8 00:00

Difficulty:   25% (medium)

Question Stats: 73% (01:29) correct 27% (01:41) wrong based on 211 sessions

### HideShow timer Statistics

Find the arithmetic mean of all roots of the following equation

$$(x+2) \sqrt{x-x^2}=0$$

A) 2
B) 1
C) 0.5
D) -1/3
E) 0.3

Originally posted by SteveNew on 25 May 2011, 13:38.
Last edited by Bunuel on 14 Dec 2016, 23:26, edited 5 times in total.
Renamed the topic.
Senior Manager  Joined: 24 Mar 2011
Posts: 290
Location: Texas
Re: Find the arithmetic mean of all roots of the following equation  [#permalink]

### Show Tags

SteveNew wrote:
Hello Guys,

Find the arithmetic mean of all roots of the following equation- see an attachment.

A 2
B 1
C 0.5
D -1/3
E 0.5

Thanks,
Steve.

Intern  Joined: 05 Apr 2011
Posts: 10
Re: Find the arithmetic mean of all roots of the following equation  [#permalink]

### Show Tags

Thank you so much Agdimple,

It was corrected.

Steve.
Senior Manager  Joined: 03 Mar 2010
Posts: 336
Schools: Simon '16 (M\$)
Re: Find the arithmetic mean of all roots of the following equation  [#permalink]

### Show Tags

1
I am getting D.

Equation is $$(x+2) \sqrt{x-x^2}=0$$
x+2=0 or x=-2
$$\sqrt{x-x^2}=0$$
x-x^2=0
x(1-x)=0
or x=0
or x=1

Average of all roots= -2+0+1/3=-1/3.
_________________
My dad once said to me: Son, nothing succeeds like success.
Director  Status: There is always something new !!
Affiliations: PMI,QAI Global,eXampleCG
Joined: 08 May 2009
Posts: 821
Re: Find the arithmetic mean of all roots of the following equation  [#permalink]

### Show Tags

the solutions are x = -2,0 and 1
the mean = -1/3.
Current Student D
Joined: 12 Aug 2015
Posts: 2548
Schools: Boston U '20 (M)
GRE 1: Q169 V154 Re: Find the arithmetic mean of all roots of the following equation  [#permalink]

### Show Tags

1
Excellent Official Questions.
Here is my solution to this one =>
The roots of the equation will be => {-2,0,1}

Hence the mean => $$\frac{-2+0+1}{3} => \frac{-1}{3}$$
Hence D
_________________
Senior Manager  G
Joined: 12 Sep 2017
Posts: 308
Re: Find the arithmetic mean of all roots of the following equation  [#permalink]

### Show Tags

Just to know, is there a possibility o create an eq multiplying both terms?
Intern  B
Joined: 18 Jul 2018
Posts: 34
Re: Find the arithmetic mean of all roots of the following equation  [#permalink]

### Show Tags

2
SteveNew wrote:
Find the arithmetic mean of all roots of the following equation

$$(x+2) \sqrt{x-x^2}=0$$

A) 2
B) 1
C) 0.5
D) -1/3
E) 0.3

Why is -2 considered a solution? the square root of a negative number doesn't exist, if you plugg in back in the equation this is impossible...
Hence, only possible solutions are 0 and 1; so C

Can someone help? Re: Find the arithmetic mean of all roots of the following equation   [#permalink] 23 Mar 2019, 06:19
Display posts from previous: Sort by

# Find the arithmetic mean of all roots of the following equation  