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

It is currently 17 Jan 2019, 09:29

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 in January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
  • The winning strategy for a high GRE score

     January 17, 2019

     January 17, 2019

     08:00 AM PST

     09:00 AM PST

    Learn the winning strategy for a high GRE score — what do people who reach a high score do differently? We're going to share insights, tips and strategies from data we've collected from over 50,000 students who used examPAL.
  • Free GMAT Strategy Webinar

     January 19, 2019

     January 19, 2019

     07:00 AM PST

     09:00 AM PST

    Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.

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

Hide Tags

 
SC Moderator
User avatar
D
Joined: 13 Apr 2015
Posts: 1687
Location: India
Concentration: Strategy, General Management
GMAT 1: 200 Q1 V1
GPA: 4
WE: Analyst (Retail)
GMAT ToolKit User Premium Member
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 12 Jan 2017, 22:05
1
St1: k = 13t + 13
t = 0 --> k is prime
t = any other integer --> k is not prime
Not Sufficient

St2: k = 17! + 13 --> 13(Some number + 1) --> k is not prime
Sufficient

Answer: B
Current Student
User avatar
D
Joined: 12 Aug 2015
Posts: 2626
Schools: Boston U '20 (M)
GRE 1: Q169 V154
GMAT ToolKit User Premium Member
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 13 Jan 2017, 00:13
Current Student
User avatar
D
Joined: 12 Aug 2015
Posts: 2626
Schools: Boston U '20 (M)
GRE 1: Q169 V154
GMAT ToolKit User Premium Member
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 13 Jan 2017, 02:25
Current Student
User avatar
D
Joined: 12 Aug 2015
Posts: 2626
Schools: Boston U '20 (M)
GRE 1: Q169 V154
GMAT ToolKit User Premium Member
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 13 Jan 2017, 04:47
Here is what i did in this Question.
We are asked about the number of factors of a Positive integer N.

Statement 1->
The only way 27*N^3 =3^3*N^3 will have 16 factors is if N is a prime number.
Hence N must be a prime number => 2 factors only.
Hence Sufficient.

Statement 2->
Since N is an integer => N^3 must be a perfect Cube.
The only perfect cube between 90 and 200 is 125.
Hence N^3 must be 125 => N must be 5 => Two factors only.
Hence sufficient.

Hence D.

_________________


MBA Financing:- INDIAN PUBLIC BANKS vs PRODIGY FINANCE!

Getting into HOLLYWOOD with an MBA!

The MOST AFFORDABLE MBA programs!

STONECOLD's BRUTAL Mock Tests for GMAT-Quant(700+)

AVERAGE GRE Scores At The Top Business Schools!

Current Student
User avatar
D
Joined: 12 Aug 2015
Posts: 2626
Schools: Boston U '20 (M)
GRE 1: Q169 V154
GMAT ToolKit User Premium Member
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 13 Jan 2017, 04:55
VP
VP
User avatar
P
Joined: 05 Mar 2015
Posts: 1003
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 13 Jan 2017, 06:43
stonecold wrote:
If a positive integer \(n\) is given by \(n=26*p\) where \(p\) is a prime number greater than 2,how many even divisors does n have ?

A)4
B)3
C)2
D)1
E)cannot be determined.




Source-> Self-Made


n=26p
=2*13*p
where p is odd(prime >2 is odd)
thus no. of even factors are
2 , 2*13 , 2*p , 2*13*p
=4

Ans A
Current Student
User avatar
D
Joined: 12 Aug 2015
Posts: 2626
Schools: Boston U '20 (M)
GRE 1: Q169 V154
GMAT ToolKit User Premium Member
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 13 Jan 2017, 06:47
rohit8865 wrote:
stonecold wrote:
If a positive integer \(n\) is given by \(n=26*p\) where \(p\) is a prime number greater than 2,how many even divisors does n have ?

A)4
B)3
C)2
D)1
E)cannot be determined.




Source-> Self-Made


n=26p
=2*13*p
where p is odd(prime >2 is odd)
thus no. of even factors are
2 , 2*13 , 2*p , 2*13*p
=4

Ans A


Counter Question->
What if p=13?


_________________


MBA Financing:- INDIAN PUBLIC BANKS vs PRODIGY FINANCE!

Getting into HOLLYWOOD with an MBA!

The MOST AFFORDABLE MBA programs!

STONECOLD's BRUTAL Mock Tests for GMAT-Quant(700+)

AVERAGE GRE Scores At The Top Business Schools!

VP
VP
User avatar
P
Joined: 05 Mar 2015
Posts: 1003
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 13 Jan 2017, 07:04
stonecold wrote:
rohit8865 wrote:
stonecold wrote:
If a positive integer \(n\) is given by \(n=26*p\) where \(p\) is a prime number greater than 2,how many even divisors does n have ?

A)4
B)3
C)2
D)1
E)cannot be determined.




Source-> Self-Made


n=26p
=2*13*p
where p is odd(prime >2 is odd)
thus no. of even factors are
2 , 2*13 , 2*p , 2*13*p
=4

Ans A


Counter Question->
What if p=13?



sure
p may be 13
then this is debatable one
on my side it will better be a DS question
Current Student
User avatar
D
Joined: 12 Aug 2015
Posts: 2626
Schools: Boston U '20 (M)
GRE 1: Q169 V154
GMAT ToolKit User Premium Member
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 13 Jan 2017, 07:19
rohit8865 wrote:
stonecold wrote:
rohit8865 wrote:

Counter Question->
What if p=13?



sure
p may be 13
then this is debatable one
on my side it will better be a DS question


We may not agree on that. :)
Since two values of the number of factors are possible => The answer cannot be determined.
Hence E.

_________________


MBA Financing:- INDIAN PUBLIC BANKS vs PRODIGY FINANCE!

Getting into HOLLYWOOD with an MBA!

The MOST AFFORDABLE MBA programs!

STONECOLD's BRUTAL Mock Tests for GMAT-Quant(700+)

AVERAGE GRE Scores At The Top Business Schools!

VP
VP
User avatar
P
Joined: 05 Mar 2015
Posts: 1003
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 13 Jan 2017, 07:26
stonecold wrote:

sure
p may be 13
then this is debatable one
on my side it will better be a DS question
[/quote]

We may not agree on that. :)
Since two values of the number of factors are possible => The answer cannot be determined.
Hence E.
[/quote]

well i have not considered the last option
Ans will be E
Current Student
User avatar
D
Joined: 12 Aug 2015
Posts: 2626
Schools: Boston U '20 (M)
GRE 1: Q169 V154
GMAT ToolKit User Premium Member
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 13 Jan 2017, 07:29
A number is said to be prime saturated if the product of all the different positive prime factors of n is less than the square root of n.
If p is a prime saturated,what is the value of p?

A)p is a perfect cube.
B)2≤p≤15



Source-> Self-Made
_________________


MBA Financing:- INDIAN PUBLIC BANKS vs PRODIGY FINANCE!

Getting into HOLLYWOOD with an MBA!

The MOST AFFORDABLE MBA programs!

STONECOLD's BRUTAL Mock Tests for GMAT-Quant(700+)

AVERAGE GRE Scores At The Top Business Schools!

VP
VP
User avatar
P
Joined: 05 Mar 2015
Posts: 1003
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 13 Jan 2017, 07:31
stonecold wrote:
If \(N\) is a positive integer,what is the value of \(N\)?
(1) \(N\) is divisible by 31.
(2) \(\frac{N}{100}\) is a prime number.



Source->Self-Made


(1) n could be 31 or 62
not suff

(2) n can be 200 or 300
not suff

combining n=31p from (1)
& 31p/100 is prime From (2)
thus n must be 3100

Ans C
SC Moderator
User avatar
D
Joined: 13 Apr 2015
Posts: 1687
Location: India
Concentration: Strategy, General Management
GMAT 1: 200 Q1 V1
GPA: 4
WE: Analyst (Retail)
GMAT ToolKit User Premium Member
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 13 Jan 2017, 07:55
St1: x = y = z = 3 --> x * y * z is not divisible by 3*7
x = 3, y = z = 21 --> x * y * z is divisible by 3*7
Not Sufficient.

St2: LCM(x, y, z) = 63
x * y * z is a multiple of 63 and hence divisible by 21
Sufficient.

Answer: B
Senior CR Moderator
User avatar
V
Status: Long way to go!
Joined: 10 Oct 2016
Posts: 1373
Location: Viet Nam
GMAT ToolKit User Premium Member
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 13 Jan 2017, 08:17
1
stonecold wrote:
A number is said to be prime saturated if the product of all the different positive prime factors of n is less than the square root of n.
If p is a prime saturated,what is the value of p?

A)p is a perfect cube.
B)2≤p≤15



Source-> Self-Made



A) \(p\) is a perfect cube. Then \(p\) could be \(3^3=27\) or \(2^3=8\). Insufficient.

B) \(2 \leq p \leq 15\)

First, \(p\) can't be a prime. Out 2, 3, 5, 7, 11, 13, left 4, 6, 8, 9, 10, 12, 14, 15
Second, \(p\) can't be in prime factorization of \(a \times b\) where \(a\) and \(b\) are prime. Out 6, 10, 14, 15. Left 4, 8, 9, 12.
Third, \(p\) can't be in form of \(a^2\) where \(a\) is prime. Out 4, 9. Left 8, 12.

8 is a cube, so 8 is prime saturated.
\(12=2^2 \times 3\). We have \(2 \times 3 = 6 > \sqrt{12}=2\sqrt{3}\) so 12 is not prime saturated.

Hence, \(p=8\). Sufficient.

The answer is B.
_________________

Actual LSAT CR bank by Broall

How to solve quadratic equations - Factor quadratic equations
Factor table with sign: The useful tool to solve polynomial inequalities
Applying AM-GM inequality into finding extreme/absolute value

New Error Log with Timer

Current Student
User avatar
D
Joined: 12 Aug 2015
Posts: 2626
Schools: Boston U '20 (M)
GRE 1: Q169 V154
GMAT ToolKit User Premium Member
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 13 Jan 2017, 09:33
Senior Manager
Senior Manager
avatar
G
Joined: 21 Aug 2016
Posts: 263
Location: India
GPA: 3.9
WE: Information Technology (Computer Software)
GMAT ToolKit User Reviews Badge
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 14 Jan 2017, 04:07
stonecold wrote:
If \(a = b^3*c^2*d\),how many positive factors does a have?

(1)\(b\), \(c\) and \(d\) are prime numbers.
(2)\(b\),\(c\),\(d\) are distinct integers.



Source->Self-Made


Clearly, the answer is A
Current Student
User avatar
D
Joined: 12 Aug 2015
Posts: 2626
Schools: Boston U '20 (M)
GRE 1: Q169 V154
GMAT ToolKit User Premium Member
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 14 Jan 2017, 08:18
1
VP
VP
User avatar
P
Joined: 05 Mar 2015
Posts: 1003
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 14 Jan 2017, 10:11
stonecold wrote:
How many positive even divisors does 96 have ?

A. 12
B. 10
C. 8
D. 6
E. Cannot be determined


96= 2^5*3
thus no. of even factors = 5*2=10

Ans B
Current Student
User avatar
D
Joined: 12 Aug 2015
Posts: 2626
Schools: Boston U '20 (M)
GRE 1: Q169 V154
GMAT ToolKit User Premium Member
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 15 Jan 2017, 13:17
Current Student
User avatar
D
Joined: 12 Aug 2015
Posts: 2626
Schools: Boston U '20 (M)
GRE 1: Q169 V154
GMAT ToolKit User Premium Member
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.  [#permalink]

Show Tags

New post 16 Jan 2017, 10:51
GMAT Club Bot
Re: STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION. &nbs [#permalink] 16 Jan 2017, 10:51

Go to page   Previous    1   2   3   4    Next  [ 72 posts ] 

Display posts from previous: Sort by

STONECOLD'S MATH CHALLENGE - PS AND DS QUESTION COLLECTION.

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


cron
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®.