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

It is currently 22 Jun 2018, 23:29

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

Events & Promotions in June
Open Detailed Calendar

If y rounded to the nearest thousandth is .00x, is x > 2?

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

Hide Tags

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 46287
If y rounded to the nearest thousandth is .00x, is x > 2? [#permalink]

Show Tags

New post 04 Feb 2015, 08:46
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

76% (01:38) correct 24% (01:03) wrong based on 139 sessions

HideShow timer Statistics

If y rounded to the nearest thousandth is .00x, is x > 2?

(1) y = 1/(5^z)
(2) z has exactly three unique factors and is a positive integer less than 9.


Kudos for a correct solution.

_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Expert Post
1 KUDOS received
Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 5931
Re: If y rounded to the nearest thousandth is .00x, is x > 2? [#permalink]

Show Tags

New post 04 Feb 2015, 10:14
1
ans C..
1) statement one does not satisfy as z=3 gives a value .008, which is >.002 but z=4 gives a value .001,which is not >.002..
2) statement two tells us that z is perfect square<9 so z=4 and nothing else ..insufficient
combined, one specific value of z will provide an answer whether x>2, sufficient
_________________

Absolute modulus :http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html


GMAT online Tutor

Expert Post
1 KUDOS received
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 46287
Re: If y rounded to the nearest thousandth is .00x, is x > 2? [#permalink]

Show Tags

New post 09 Feb 2015, 06:16
1
2
Bunuel wrote:
If y rounded to the nearest thousandth is .00x, is x > 2?

(1) y = 1/(5^z)
(2) z has exactly three unique factors and is a positive integer less than 9.


Kudos for a correct solution.


VERITAS PREP OFFICIAL SOLUTION:

Solution: C

Start with the easier of the two statements. If we only have the stimulus and statement (2), we don’t know what z refers to, so statement (2) is NOT sufficient. If we have only the stimulus and statement (1), we don’t know the value of z. This is usually enough to render a statement insufficient, but if you’re nervous, try a few numbers. If z is 3, y = 1/125 = .008; that says that x = 8. If z is 4, y is 1/625 = .0016; that says that x = 2. The statements conflict, so (1) is NOT sufficient. Together, z must be 4 – any number that has exactly three unique factors is a prime number squared, and the only number less than 9 that is a prime number squared is 4. (C).
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Intern
Intern
avatar
B
Joined: 18 Sep 2016
Posts: 26
Re: If y rounded to the nearest thousandth is .00x, is x > 2? [#permalink]

Show Tags

New post 12 Aug 2017, 06:58
Bunuel wrote:
Bunuel wrote:
If y rounded to the nearest thousandth is .00x, is x > 2?

(1) y = 1/(5^z)
(2) z has exactly three unique factors and is a positive integer less than 9.


Kudos for a correct solution.


VERITAS PREP OFFICIAL SOLUTION:

Solution: C

Start with the easier of the two statements. If we only have the stimulus and statement (2), we don’t know what z refers to, so statement (2) is NOT sufficient. If we have only the stimulus and statement (1), we don’t know the value of z. This is usually enough to render a statement insufficient, but if you’re nervous, try a few numbers. If z is 3, y = 1/125 = .008; that says that x = 8. If z is 4, y is 1/625 = .0016; that says that x = 2. The statements conflict, so (1) is NOT sufficient. Together, z must be 4 – any number that has exactly three unique factors is a prime number squared, and the only number less than 9 that is a prime number squared is 4. (C).


How come z=6 r 8? also. 6 has unique 3 factors 6=2*3*1
1 KUDOS received
Manager
Manager
avatar
S
Joined: 13 Mar 2013
Posts: 173
Location: United States
Concentration: Leadership, Technology
GPA: 3.5
WE: Engineering (Telecommunications)
Re: If y rounded to the nearest thousandth is .00x, is x > 2? [#permalink]

Show Tags

New post 12 Aug 2017, 08:41
1
Bunuel wrote:
Bunuel wrote:
If y rounded to the nearest thousandth is .00x, is x > 2?

(1) y = 1/(5^z)
(2) z has exactly three unique factors and is a positive integer less than 9.


Kudos for a correct solution.


VERITAS PREP OFFICIAL SOLUTION:

Solution: C

Start with the easier of the two statements. If we only have the stimulus and statement (2), we don’t know what z refers to, so statement (2) is NOT sufficient. If we have only the stimulus and statement (1), we don’t know the value of z. This is usually enough to render a statement insufficient, but if you’re nervous, try a few numbers. If z is 3, y = 1/125 = .008; that says that x = 8. If z is 4, y is 1/625 = .0016; that says that x = 2. The statements conflict, so (1) is NOT sufficient. Together, z must be 4 – any number that has exactly three unique factors is a prime number squared, and the only number less than 9 that is a prime number squared is 4. (C).


How come z=6 r 8? also. 6 has unique 3 factors 6=2*3*1



As per the question (2) z has exactly three unique factors and is a positive integer less than 9.
Hence Z=4 , factors are 1, 2, 4
a is factor b means , b completely divides a .

if you check for 6 . Its factors are 1, 2, 3, 6

Also other way to calculate factors ( a^b * c^d ) where a and c are prime , then the number of factors = (b+1) (d+1)

Regards,
Press Kudos if you like the post .
_________________

Regards ,

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 46287
Re: If y rounded to the nearest thousandth is .00x, is x > 2? [#permalink]

Show Tags

New post 12 Aug 2017, 09:17
tejasridarsi wrote:
Bunuel wrote:
Bunuel wrote:
If y rounded to the nearest thousandth is .00x, is x > 2?

(1) y = 1/(5^z)
(2) z has exactly three unique factors and is a positive integer less than 9.


Kudos for a correct solution.


VERITAS PREP OFFICIAL SOLUTION:

Solution: C

Start with the easier of the two statements. If we only have the stimulus and statement (2), we don’t know what z refers to, so statement (2) is NOT sufficient. If we have only the stimulus and statement (1), we don’t know the value of z. This is usually enough to render a statement insufficient, but if you’re nervous, try a few numbers. If z is 3, y = 1/125 = .008; that says that x = 8. If z is 4, y is 1/625 = .0016; that says that x = 2. The statements conflict, so (1) is NOT sufficient. Together, z must be 4 – any number that has exactly three unique factors is a prime number squared, and the only number less than 9 that is a prime number squared is 4. (C).


How come z=6 r 8? also. 6 has unique 3 factors 6=2*3*1


6 has four factors not three: 1, 2, 3, and 6.
8 has four factors not three: 1, 2, 4, and 8.

Remember a positive integer is a factor of itself.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Manager
Manager
User avatar
S
Joined: 23 May 2017
Posts: 226
Concentration: Finance, Accounting
WE: Programming (Energy and Utilities)
CAT Tests
Re: If y rounded to the nearest thousandth is .00x, is x > 2? [#permalink]

Show Tags

New post 12 Aug 2017, 09:41
Bunuel - Pardon me for this silly doubt.

Don't we need numbers after thousandth to do rounding.

I marked this as A as i thought we cannot round off y = 0.008 as it does not have anything after 8 to round off
and rest all values of y tell x < 2

Can you please clarify the rounding concept?
_________________

If you like the post, please award me Kudos!! It motivates me

Senior Manager
Senior Manager
User avatar
P
Joined: 29 Jun 2017
Posts: 499
GPA: 4
WE: Engineering (Transportation)
GMAT ToolKit User Premium Member Reviews Badge
If y rounded to the nearest thousandth is .00x, is x > 2? [#permalink]

Show Tags

New post Updated on: 17 Aug 2017, 10:03
1) take z=1, y=.02, take z= 3 then y= .008 , hence A,D ruled out
2) z can be anything so B ruled out

combine 1,2 z has 3 unique factors i.e. z is a perfect square hence its is 4 which is less than 9 as given , the factors are 1,2,4
so the value of y when z=4 is .0016 and when rounded off gives value .002 which is x = 2 and clearly is x>2 we have definite NO it is not
hence C is answer.
_________________

Give Kudos for correct answer and/or if you like the solution.


Originally posted by sahilvijay on 12 Aug 2017, 11:27.
Last edited by sahilvijay on 17 Aug 2017, 10:03, edited 1 time in total.
SVP
SVP
User avatar
P
Joined: 26 Mar 2013
Posts: 1677
Reviews Badge CAT Tests
Re: If y rounded to the nearest thousandth is .00x, is x > 2? [#permalink]

Show Tags

New post 13 Aug 2017, 04:38
Bunuel wrote:
If y rounded to the nearest thousandth is .00x, is x > 2?

(1) y = 1/(5^z)
(2) z has exactly three unique factors and is a positive integer less than 9.


Kudos for a correct solution.



Dear Bunuel

The question says ''if y is rounded'. In statement 1, if z= 2....then y =0.008. I do not see any rounding process. 'Y' naturally without rounding is 0.008. How do we assume that 0.008 is rounded?
Re: If y rounded to the nearest thousandth is .00x, is x > 2?   [#permalink] 13 Aug 2017, 04:38
Display posts from previous: Sort by

If y rounded to the nearest thousandth is .00x, is x > 2?

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


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®.