Find all School-related info fast with the new School-Specific MBA Forum

It is currently 20 Nov 2014, 14:59

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

I. If p is a prime number greater than 2, what is the value

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Director
Director
User avatar
Joined: 25 Oct 2006
Posts: 652
Followers: 7

Kudos [?]: 206 [0], given: 6

I. If p is a prime number greater than 2, what is the value [#permalink] New post 10 Jun 2007, 17:44
I. If p is a prime number greater than 2, what is the value of p?
(1) There are a total of 100 prime numbers between 1 and p+1
(2) There are a total of p prime numbers between 1 and 3,912

Could anyone suggest the best way to solve this problem?

II) [ x, 3, 1, 12, 8 ]
If x is an integer, is the median of the 5 numbers shown greater than the average (arithmetic mean) of the 5 numbers?

1) x > 6
2) x is greater than the median of the 5 numbers

IMO E
Manager
Manager
avatar
Joined: 23 Dec 2006
Posts: 136
Followers: 1

Kudos [?]: 9 [0], given: 0

Re: Number property [#permalink] New post 10 Jun 2007, 17:59
priyankur_saha@ml.com wrote:
I. If p is a prime number greater than 2, what is the value of p?
(1) There are a total of 100 prime numbers between 1 and p+1
(2) There are a total of p prime numbers between 1 and 3,912

Could anyone suggest the best way to solve this problem?

II) [ x, 3, 1, 12, 8 ]
If x is an integer, is the median of the 5 numbers shown greater than the average (arithmetic mean) of the 5 numbers?

1) x > 6
2) x is greater than the median of the 5 numbers

IMO E


Question 1: Remember we only need to know whether we're able to solve the problem. Both of those statements give enough information to do so, but figuring the answer is beyond the scope of the problem. The answer is D because if we had enough time, we could find p from both statements.
Manager
Manager
avatar
Joined: 07 May 2007
Posts: 181
Followers: 2

Kudos [?]: 15 [0], given: 0

 [#permalink] New post 10 Jun 2007, 18:49
Exactly.

First question is a classic example of problems requiring some out of the box thinking! Answer is D

I think E is the correct asnwer for second question
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jul 2004
Posts: 5093
Location: Singapore
Followers: 19

Kudos [?]: 161 [0], given: 0

 [#permalink] New post 10 Jun 2007, 19:03
Qn1:

St1:
Sufficient. I'm too lazy to count, but you could list them if you like, though DS wouldn't require you to do that.

St2:
Sufficient. Same as above.

Ans D
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jul 2004
Posts: 5093
Location: Singapore
Followers: 19

Kudos [?]: 161 [0], given: 0

 [#permalink] New post 10 Jun 2007, 19:07
Qn2:

From the set, we can derive that:
x<=5, median <mean>6 median > mean

St1:
Sufficient. We can asnwer the question.

St2:
Sufficient. We can answer that too.

Ans D
Director
Director
User avatar
Joined: 13 Mar 2007
Posts: 546
Schools: MIT Sloan
Followers: 4

Kudos [?]: 24 [0], given: 0

 [#permalink] New post 10 Jun 2007, 22:23
go with E for 2nd

st1, consider x=7 , median is greater than mean
consider x = 10,000000000 , median is lesser than mean :)


st2, max median for the given set of 5#s = 8

consider x=9, median > mean
consider x = 10^234654, median <mean>8 same as st2

hence E
Intern
Intern
User avatar
Joined: 14 May 2007
Posts: 26
Followers: 0

Kudos [?]: 0 [0], given: 0

 [#permalink] New post 11 Jun 2007, 01:48
I. If p is a prime number greater than 2, what is the value of p?
(1) There are a total of 100 prime numbers between 1 and p+1
(2) There are a total of p prime numbers between 1 and 3,912

Could anyone suggest the best way to solve this problem?


----------------------------------------------------------------------------

Well your approach should be:

1. To identify p you need to know a unique identifier for it. Lets consider the fisrt option"There are a total of 100 prime numbers between 1 and p+1 "

Since p is prime(given), then p+1 cannot be prime. So p is the 100th prime number --> hence unique

So we can find out p using statement 1 only.
Note that you dont really need to calculate the value of p...just think of a way of identifying it

2.Now consider option 2:"There are a total of p prime numbers between 1 and 3,912 "

To begin with...I dont know how many prime number are between 1 and 3,912...but do i need to know it for solving this question...The answer is 'NO'

All you need to know is that there is a unique no. (say X) and according to question X = p.

So we can find out p using statement 2 only.

Hence answer is D

______________________________________________________
______________________________________________________
Intern
Intern
User avatar
Joined: 14 May 2007
Posts: 26
Followers: 0

Kudos [?]: 0 [0], given: 0

2nd Question [#permalink] New post 11 Jun 2007, 01:57
II) [ x, 3, 1, 12, 8 ]
If x is an integer, is the median of the 5 numbers shown greater than the average (arithmetic mean) of the 5 numbers?

1) x > 6
2) x is greater than the median of the 5 numbers

------------------------------------------------------------------------------

Lets consider statement 1:
x> 6
Then my possible sets are:
1. [1,3,x,8,12] -->
Median = x = 7
Mean = 6.2

2. [1,3,8,x,12] (x = 8 or 9 or 10 or 11)
Median = 8
Mean = 6.4 to 7
Median > Mean

3. [1,3,8,12,x] ( x>= 12)
Median = 8
Mean >= 7.2
Median > Mean or Median < Mean both possible

Hence, staement 1 alone not sufficient

Consider statement 2:"X is greater than the median of the 5 numbers"

All possible sets are:

A. When x<6> 3

(i)[1,3,x,8,12]

Median = 4, 5, 6
Mean = 5.6 , 5.8, 6
Median < Mean or Mean = Median both possible
x= Median

(ii) [1,x,3,8,12] (x <= 3)
Median = 3
Mean = 5 , 5.2, 5.4
Median < Mean
x <Median> 6

Then my possible sets are:
1. [1,3,x,8,12] -->
Median = x = 7
Mean = 6.2
Median > Mean
X = Median
2. [1,3,8,x,12] (x = 8 or 9 or 10 or 11)
Median = 8
Mean = 6.4 to 7
Median > Mean
x >= Median
3. [1,3,8,12,x] ( x>= 12)
Median = 8
Mean >= 7.2
Median > Mean or Median <Mean> Median


Sets 2 and 3 above are the ones which become applicable for option "Both Statement Together"
But even then we cannot say conclusively whether Median > Mean
Hence answer is E
Director
Director
User avatar
Joined: 30 Nov 2006
Posts: 592
Location: Kuwait
Followers: 11

Kudos [?]: 159 [0], given: 0

 [#permalink] New post 11 Jun 2007, 04:42
For question " I ",

(1) we can count 100 prime numbers starting from 2 and that will lead us to the value of P

statement 1 is sufficient

(2) we can count the number of prime numbers here also. It's possibly, not easy, but the information is sufficient to answer the question

statement 2 is sufficient

ANSWER: D
__________________________________________________________________

For question " II ",

(1) The fact that x>6 doesn't lead us to a median of either X or 8. Each median results in a different relation between the median and the mean.

statement 1 is insufficient

(2) If X is greater than the median, then the median has to be 8. Yet, X can be a really huge integer and thus inflate the mean OR can be 7 which results in a much smaller mean and thus switched the relationship between the median and the mean

statement 2 is insufficient

ANSWER: E
Senior Manager
Senior Manager
User avatar
Joined: 04 Mar 2007
Posts: 447
Followers: 1

Kudos [?]: 14 [0], given: 0

Re: Number property [#permalink] New post 14 Jun 2007, 09:09
priyankur_saha@ml.com wrote:
I. If p is a prime number greater than 2, what is the value of p?
(1) There are a total of 100 prime numbers between 1 and p+1
(2) There are a total of p prime numbers between 1 and 3,912

My answer is D
We don't need to count. Sufficient only to know that it's possible to count if needed.


II) [ x, 3, 1, 12, 8 ]
If x is an integer, is the median of the 5 numbers shown greater than the average (arithmetic mean) of the 5 numbers?

1) x > 6
2) x is greater than the median of the 5 numbers

IMO E
My answer is E here as x in both cases can be as small as 7 or 9, and as big as 1000 000 000...


Please provide the OAs
Re: Number property   [#permalink] 14 Jun 2007, 09:09
    Similar topics Author Replies Last post
Similar
Topics:
5 Experts publish their posts in the topic If p is a prime number greater than 2, what is the value of aljatar 13 28 Mar 2010, 04:56
2 Experts publish their posts in the topic If p is a prime number greater than 2, what is the value of 700orbust 9 12 Jul 2008, 14:46
Experts publish their posts in the topic If p is a prime number greater than 2, what is the value of sondenso 6 05 Apr 2008, 00:22
If n = 4p, where p is a prime number greater than 2, how desiguy 7 10 Dec 2005, 19:30
If n = 4p, where p is a prime number greater than 2 how many Priti 8 14 Aug 2005, 12:43
Display posts from previous: Sort by

I. If p is a prime number greater than 2, what is the value

  Question banks Downloads My Bookmarks Reviews Important topics  


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

Powered by phpBB © phpBB Group and phpBB SEO

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®.