NEW HERE? LEARN MORE
closeclose
Last visit was: 25 Apr 2024, 20:23 It is currently 25 Apr 2024, 20:23
Decision Tracker
My Rewards
New posts
New comers' posts

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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

3 GMAT Prep DS - Need help Please

User avatar
anujkm
Intern
Intern
Joined: 01 Mar 2006
Posts: 1
Own Kudos [?]: [0]
Given Kudos: 0
Send PM
3 GMAT Prep DS - Need help Please [#permalink] New post   Updated on: 30 May 2007, 19:59
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
Hide Show timer Statistics
Any help in solving these questions is appreciated ..



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Data Sufficiency (DS) Forum
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!

Originally posted by anujkm on 28 May 2007, 18:04.
Last edited by anujkm on 30 May 2007, 19:59, edited 1 time in total.
User avatar
ggarr
Senior Manager
Senior Manager
Joined: 12 Jun 2006
Posts: 263
Own Kudos [?]: 691 [0]
Given Kudos: 1
Send PM
Re: 3 GMAT Prep DS - Need help Please [#permalink] New post   28 May 2007, 21:31
My answer is A:
h(n) = the prod. of all the even integers from 2 - n.
h(100) = the prod. of all the even integers from 2 - 100; 2(4)6(8) ..... = 2(2*2)(2*3)(2*2*2*) ....
p is defined as the smallest prime factor of h(100)+1. the smalles prime factor of h(100), which is the product of all the even integers b/w 2 and 100, is 2. 2 + 1 =3.
avatar
joroivanov
Intern
Intern
Joined: 16 May 2007
Posts: 12
Own Kudos [?]: 2 [0]
Given Kudos: 0
Send PM
Re: 3 GMAT Prep DS - Need help Please [#permalink] New post   29 May 2007, 10:26
I will skip the first Q as I have no explanation for the answer. It's crazy that you can get that kind of a Q so early:)

For #2:

Since students either like or dislike either food (i will abreviate them "LB" and "BS"), by knowing what they don't like you actually know what they like.

We need the # of students who dislike LB but like BS

You know that 2/3 of the students dislike LB and of those 2/5 like BS (1-3/5). So, in essence, all you need to know is the actual number of students who dislike LB.

(1) Sufficient. Knowing the total number of students in the cafeteria, you can find the # of the students who dislike LB. (120*2/3 = 80)

(2) Sufficient. Number of students who like LB = 1/3 of all students = 40.
You can use that to find the number of students who dislike LB (80).

Answer D
avatar
joroivanov
Intern
Intern
Joined: 16 May 2007
Posts: 12
Own Kudos [?]: 2 [0]
Given Kudos: 0
Send PM
Re: 3 GMAT Prep DS - Need help Please [#permalink] New post   29 May 2007, 10:32
For Q #3:

The problem tells you that z/y and y/x are integers. I will refer to this as (M)


(1) Sufficient. For zx to be even, at least one of the numbers has to be an even number. However, for (M) to hold true z cannot be an odd number. Which means, it has to be even.

(2) Sufficient. Odd numbers are not divisible by even numbers, so if y is even then z has to be even.

Answer D
User avatar
LM
Senior Manager
Senior Manager
Joined: 03 Sep 2006
Posts: 446
Own Kudos [?]: 6776 [0]
Given Kudos: 33
Send PM
GMAT ToolKit User
Re: 3 GMAT Prep DS - Need help Please [#permalink] New post   29 May 2007, 19:30
anujkm wrote:
Any help in solving these questions is appreciated ..


ANswer for the question 1 is straight away result frmo Wilson's Theroem. Please check Wilson's theorem in WIkipedia and remember it.
User avatar
LM
Senior Manager
Senior Manager
Joined: 03 Sep 2006
Posts: 446
Own Kudos [?]: 6776 [0]
Given Kudos: 33
Send PM
GMAT ToolKit User
Re: 3 GMAT Prep DS - Need help Please [#permalink] New post   29 May 2007, 19:44
anujkm wrote:
Any help in solving these questions is appreciated ..


Please remember this.... WILSON's THEOREM

p divides (p-1)!+1 if p is prime. The converse is also true. For instance, 7 is prime, and 7 divides (6!)+1=721




.
User avatar
LM
Senior Manager
Senior Manager
Joined: 03 Sep 2006
Posts: 446
Own Kudos [?]: 6776 [0]
Given Kudos: 33
Send PM
GMAT ToolKit User
Re: 3 GMAT Prep DS - Need help Please [#permalink] New post   29 May 2007, 19:49
joroivanov wrote:
I will skip the first Q as I have no explanation for the answer. It's crazy that you can get that kind of a Q so early:)

For #2:

Since students either like or dislike either food (i will abreviate them "LB" and "BS"), by knowing what they don't like you actually know what they like.

We need the # of students who dislike LB but like BS

You know that 2/3 of the students dislike LB and of those 2/5 like BS (1-3/5). So, in essence, all you need to know is the actual number of students who dislike LB.

(1) Sufficient. Knowing the total number of students in the cafeteria, you can find the # of the students who dislike LB. (120*2/3 = 80)

(2) Sufficient. Number of students who like LB = 1/3 of all students = 40.
You can use that to find the number of students who dislike LB (80).

Answer D


the key as you mentioned is by knowing what they don't like you actually know what they like.
User avatar
LM
Senior Manager
Senior Manager
Joined: 03 Sep 2006
Posts: 446
Own Kudos [?]: 6776 [0]
Given Kudos: 33
Send PM
GMAT ToolKit User
Re: 3 GMAT Prep DS - Need help Please [#permalink] New post   29 May 2007, 19:54
joroivanov wrote:
For Q #3:

The problem tells you that z/y and y/x are integers. I will refer to this as (M)


(1) Sufficient. For zx to be even, at least one of the numbers has to be an even number. However, for (M) to hold true z cannot be an odd number. Which means, it has to be even.

(2) Sufficient. Odd numbers are not divisible by even numbers, so if y is even then z has to be even.

Answer D


Is there no possibility that Z might be odd number?? :roll:
User avatar
LM
Senior Manager
Senior Manager
Joined: 03 Sep 2006
Posts: 446
Own Kudos [?]: 6776 [0]
Given Kudos: 33
Send PM
GMAT ToolKit User
Re: 3 GMAT Prep DS - Need help Please [#permalink] New post   29 May 2007, 19:55
anujkm wrote:
Any help in solving these questions is appreciated ..


You've attached the same file twice. Please remove one of them.
User avatar
ywilfred
SVP
SVP
Joined: 07 Jul 2004
Posts: 2004
Own Kudos [?]: 1899 [0]
Given Kudos: 0
Location: Singapore
Send PM
Re: 3 GMAT Prep DS - Need help Please [#permalink] New post   29 May 2007, 20:15
Question 1 has been extensively discussed in this forum. You can do a search and find the solutions.
avatar
joroivanov
Intern
Intern
Joined: 16 May 2007
Posts: 12
Own Kudos [?]: 2 [0]
Given Kudos: 0
Send PM
Re: 3 GMAT Prep DS - Need help Please [#permalink] New post   29 May 2007, 20:17
LM - I think not. :)

if zx is the product of an odd number z and an even number x, then what is stated in the question stem wouldn't hold true (z/y and y/x wouldn't be integers).

If we assume that z is odd, for zx to be even, x has to be even. But then for z/y to be an integer, y has to be odd. However, if y is odd, for y/x to be an integer x has to be odd, which contradicts our first assumption (that x is even).



LM wrote:
joroivanov wrote:
For Q #3:

The problem tells you that z/y and y/x are integers. I will refer to this as (M)


(1) Sufficient. For zx to be even, at least one of the numbers has to be an even number. However, for (M) to hold true z cannot be an odd number. Which means, it has to be even.

(2) Sufficient. Odd numbers are not divisible by even numbers, so if y is even then z has to be even.

Answer D


Is there no possibility that Z might be odd number?? :roll:
User avatar
hsk
Intern
Intern
Joined: 03 Apr 2006
Posts: 34
Own Kudos [?]: 91 [0]
Given Kudos: 0
Send PM
Re: 3 GMAT Prep DS - Need help Please [#permalink] New post   29 May 2007, 20:58
Quote:
Question 1 has been extensively discussed in this forum. You can do a search and find the solutions.


does anyone have a link? I am having trouble finding the past discussion
User avatar
hsk
Intern
Intern
Joined: 03 Apr 2006
Posts: 34
Own Kudos [?]: 91 [0]
Given Kudos: 0
Send PM
Re: 3 GMAT Prep DS - Need help Please [#permalink] New post   30 May 2007, 07:26
can someone please explain number one or show me the link for the past discussions.



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Data Sufficiency (DS) Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
GMAT Club Bot
gmatclubot
Re: 3 GMAT Prep DS - Need help Please [#permalink]
30 May 2007, 07:26
Moderators:
Bunuel
Math Expert
92915 posts
yashikaaggarwal
Senior Moderator - Masters Forum
3137 posts
GMATBusters
GMAT Tutor
1905 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions