It is currently 18 Feb 2018, 23:42

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# r=?

Author Message
TAGS:

### Hide Tags

Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 4880
GPA: 3.82

### Show Tags

23 May 2017, 01:25
00:00

Difficulty:

25% (medium)

Question Stats:

63% (00:38) correct 38% (00:43) wrong based on 40 sessions

### HideShow timer Statistics

r=?

1) $$r^3-r^2=0$$
2) $$r=-r$$
[Reveal] Spoiler: OA

_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
Find a 10% off coupon code for GMAT Club members.
“Receive 5 Math Questions & Solutions Daily”
Unlimited Access to over 120 free video lessons - try it yourself

Senior Manager
Joined: 06 Jan 2015
Posts: 312
Location: India
Concentration: Operations, Finance
GPA: 3.35
WE: Information Technology (Computer Software)

### Show Tags

23 May 2017, 02:24
MathRevolution wrote:
r=?

1) $$r^3-r^2=0$$
2) $$r=-r$$

1) $$r^3-r^2=0$$=$$r^2(r-1)=0$$
r=0 or 1

2) $$r=-r$$ => 2r=0 i,e r=0

Hence B
_________________

आत्मनॊ मोक्षार्थम् जगद्धिताय च

Resource: GMATPrep RCs With Solution

Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 4880
GPA: 3.82

### Show Tags

25 May 2017, 00:16
==> In the original condition, there is 1 variable (r), and in order to match the number of variables to the number of equations, there must be 1 equation. Since there is 1 for con 1) and 1 for con 2), D is most likely to be the answer.
For con 1), from r2(r-1)=0, you get r=0,1, hence it is not unique and not sufficient.
For con 2), from 2r=0, you get r=0, hence it is unique and sufficient. Therefore, the answer is B.

_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
Find a 10% off coupon code for GMAT Club members.
“Receive 5 Math Questions & Solutions Daily”
Unlimited Access to over 120 free video lessons - try it yourself

Re: r=?   [#permalink] 25 May 2017, 00:16
Display posts from previous: Sort by