NEW HERE? LEARN MORE
closeclose
Last visit was: 25 Apr 2024, 19:52 It is currently 25 Apr 2024, 19:52
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

This one is a tough one. Good luck If 2^n =

User avatar
Paul
CEO
CEO
Joined: 15 Dec 2003
Posts: 2709
Own Kudos [?]: 1538 [0]
Given Kudos: 0
Send PM
This one is a tough one. Good luck If 2^n = [#permalink] New post   06 Nov 2004, 14:53
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
This one is a tough one. Good luck :lol:

If 2^n = 29*30*31*...100, then n = ?

a) 90
b) 97
c) 79
d) 70
e) None of the above



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 Problem Solving (PS) 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!
User avatar
venksune
Director
Director
Joined: 16 Jun 2004
Posts: 510
Own Kudos [?]: 159 [0]
Given Kudos: 0
Send PM
Re: This one is a tough one. Good luck If 2^n = [#permalink] New post   06 Nov 2004, 15:54
I think E. There will be a '0' in the unit digit of the big number (in 100!/28!. Note: 29*30*31...*100 = 100!/28!)and anything to the power of 2 will have a unit digit other than 0.

So, E.
avatar
Jigar
Intern
Intern
Joined: 24 Oct 2004
Posts: 3
Own Kudos [?]: [0]
Given Kudos: 0
Send PM
Re: This one is a tough one. Good luck If 2^n = [#permalink] New post   06 Nov 2004, 21:08
I thought of the same.....

do you guyz have good practice material to improve on numbers and factors on DS?? Plus....rate and time and distance.....this is what iam really bad at and this is what pulls down my score!
User avatar
Dookie
Manager
Manager
Joined: 19 May 2004
Posts: 146
Own Kudos [?]: 31 [0]
Given Kudos: 0
Send PM
Re: This one is a tough one. Good luck If 2^n = [#permalink] New post   07 Nov 2004, 11:33
I also think it's E.

This number will have some other prime factors except 2...
User avatar
Paul
CEO
CEO
Joined: 15 Dec 2003
Posts: 2709
Own Kudos [?]: 1538 [0]
Given Kudos: 0
Send PM
Re: This one is a tough one. Good luck If 2^n = [#permalink] New post   07 Nov 2004, 15:40
OA is E or exact answer should be 72
I used "possessed"'s method.
100/2 = 50
50/2 = 25
25/2 = 12
12/2 = 6
6/2 = 3
3/2 = 1
Sum is 97
But the series start at 29 so you have to remove all factors of 2 included in first 29 integers.
29/2 = 14
14/2 = 7
7/2 = 3
3/2 = 1
Sum is 25
Answer should be 97-25 = 72
The reason why we are succinctly dividing by 2 is because we are trying to find the succinct exponents of 2. The first time we are dividing by 2, we are finding all numbers divisible by 2. The second time we are dividing by 2, we are finding all numbers divisible by 4 which contain 2^2 and so on so forth.



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 Problem Solving (PS) 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: This one is a tough one. Good luck If 2^n = [#permalink]
07 Nov 2004, 15:40
Moderators:
Bunuel
Math Expert
92915 posts
yashikaaggarwal
Senior Moderator - Masters Forum
3137 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