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

It is currently 30 Sep 2014, 22:08

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

M01 #10

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Manager
Manager
User avatar
Status: livin on a prayer!!
Joined: 12 May 2011
Posts: 125
Location: Australia
Followers: 0

Kudos [?]: 17 [0], given: 1

Re: M01 #10 [#permalink] New post 04 Nov 2011, 18:56
Answer is 300, D.

Units Digit: 007, 017....097 = 10
Tens Digit: 070, 071...079 = 10

So there are 10 + 10 = 20 instances of 7 in each hundred numbers. So in 1000 numbers, there are 10 x 100 numbers = 20 x 10 = 200 instances of 7 in 1000 for units and tens digits.

Hundreds digit: 700, 701...799 = 100 instances of 7 for the hundreds digit.

So from 1-1000, there are 200 + 100 = 300 instances of 7.

Hope that helps!!!
_________________

Aim for the sky! (800 in this case)
If you like my post, please give me Kudos :)

Manager
Manager
avatar
Joined: 10 Jan 2011
Posts: 244
Location: India
GMAT Date: 07-16-2012
GPA: 3.4
WE: Consulting (Consulting)
Followers: 0

Kudos [?]: 21 [0], given: 25

Reviews Badge
Re: M01 #10 [#permalink] New post 18 Nov 2011, 01:42
single digit number 7 will appear once.
2 digit number 7 will appear = 9 time at unit digit and 10 times at 10th digit. = 19 times
3 digit number 7 will appear = 100 times for 100th digit + 90 times fo 10th times +90 times for 90 times for unit digit = total 280

so total number of times 7 appears between 1 to 1000 = 280+19+1 = 300
_________________

-------Analyze why option A in SC wrong-------

Intern
Intern
avatar
Joined: 04 Aug 2011
Posts: 45
Location: United States
Concentration: Technology, Leadership
GMAT 1: 570 Q45 V25
GPA: 4
WE: Information Technology (Computer Software)
Followers: 0

Kudos [?]: 14 [0], given: 20

Re: M01 #10 [#permalink] New post 14 Jan 2012, 20:57
IMO - D
Best way to solve this .

100's place = 1x10x10 = 100
10's place = 10x1x10 = 100
1's place = 10x10x1 = 100
Intern
Intern
avatar
Joined: 26 Jun 2014
Posts: 3
Followers: 0

Kudos [?]: 1 [0], given: 106

M01 #10 [#permalink] New post 18 Jul 2014, 10:00
Surely the easiest way to resolve this is to use the fact that the 7 appears one tenth of the time. So out of the thousand numbers, it appears in the 100's slot 1/10(1000)=100 times, in the 10's slot 1/10(1000)=100 times, and in the units slot 1/10(1000)=100 times. Is my thinking incorrect?
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23064
Followers: 3539

Kudos [?]: 27255 [0], given: 2725

Re: M01 #10 [#permalink] New post 18 Jul 2014, 11:25
Expert's post
Chakolate wrote:
Surely the easiest way to resolve this is to use the fact that the 7 appears one tenth of the time. So out of the thousand numbers, it appears in the 100's slot 1/10(1000)=100 times, in the 10's slot 1/10(1000)=100 times, and in the units slot 1/10(1000)=100 times. Is my thinking incorrect?



Yes. Check here: m01-70917.html#p826207
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

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?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Re: M01 #10   [#permalink] 18 Jul 2014, 11:25
    Similar topics Author Replies Last post
Similar
Topics:
Experts publish their posts in the topic M01-10 Bunuel 1 15 Sep 2014, 23:14
M01Q10 DenisSh 1 06 Sep 2009, 23:25
1 Experts publish their posts in the topic m01 #10 bipolarbear 1 24 Jul 2009, 07:50
Experts publish their posts in the topic M01 #10 vannu 2 22 Jul 2009, 18:46
29 Experts publish their posts in the topic M01 #10 redbeanaddict 24 29 Sep 2008, 23:43
Display posts from previous: Sort by

M01 #10

  Question banks Downloads My Bookmarks Reviews Important topics  

Go to page   Previous    1   2   [ 25 posts ] 

Moderators: Bunuel, WoundedTiger



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®.