It is currently 23 Jun 2017, 05:19

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

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

m01 Q10 (is official answer correct?)

Author Message
Manager
Joined: 28 Jul 2009
Posts: 118

Show Tags

31 Aug 2009, 01:14
Hi, I just answered m01 and I'm not sure the official answer to q10 is correct.
Q: How many times will the digit 7 be written when listing the integers 1 to 1000?
OA: 300
My calculation: 280

But when I did the calculations, I came up with:
1-10: 7 (1 no.)
11-99: 17,27,37,...97 (9 nos.)
70,71,72,...79 (10 nos.)
100-199: 107,117,127,...197 (10 nos.)
170,171,172,...190 (10 nos.)
So for 100-199, 200-299, 300-399,...900-900 EXCEPT 700-799, there are 8*20 sevens = 160
For 700-799, 100 nos.
So, in total that's 160+100+10+9+1=280.

I think the official answer double-counted the 20 nos. in 100-999, it included 20 nos. in 700 but still added a full 100 nos. in 700-799.

Do correct me if I'm wrong please.
CIO
Joined: 02 Oct 2007
Posts: 1218

Show Tags

31 Aug 2009, 02:32
Hi vanilla,

m01-70917.html

You can find the list of questions and links to their discussions in this thread:

_________________

Welcome to GMAT Club!

Want to solve GMAT questions on the go? GMAT Club iPhone app will help.
Result correlation between real GMAT and GMAT Club Tests
Are GMAT Club Test sets ordered in any way?

Take 15 free tests with questions from GMAT Club, Knewton, Manhattan GMAT, and Veritas.

GMAT Club Premium Membership - big benefits and savings

Re: m01 Q10 (is official answer correct?)   [#permalink] 31 Aug 2009, 02:32
Similar topics Replies Last post
Similar
Topics:
M01Q10 1 07 Sep 2009, 00:42
m01 1 27 May 2009, 11:42
Need help with m01 #26--answer incorrect? 0 11 Nov 2008, 13:17
5 M01 27 11 14 Jan 2012, 22:54
19 M01-Q15 20 27 Jun 2014, 11:15
Display posts from previous: Sort by

m01 Q10 (is official answer correct?)

Moderator: Bunuel

 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®.