It is currently 19 Oct 2017, 17:10

### 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

# quant question

Author Message
TAGS:

### Hide Tags

Manager
Joined: 21 Feb 2010
Posts: 206

Kudos [?]: 41 [0], given: 1

### Show Tags

31 May 2010, 13:16
hi everyone,
is there any other way to do the following question? i understand the explanation provided by the GMAT club. however i think this is a time-consuming approach. any short cut to this question? thanks!

How many times will the digit 7 be written when listing the integers from 1 to 1000?
• 110
• 111
• 271
• 300
• 304
There are several ways to count the number of times 7 appears between 7 and 997. One way is to consider the number of 7's in single, double, and triple digit numbers separately.
One-digit numbers: 7 is the only one-digit number.
Two-digit numbers: 7 could be the first digit or the second digit. Case 1: 7 is the first digit. There are 9 ways to place 7 as the first digit of a two-digit number. Case 2: There are 10 ways to place the second digit, i.e. 0-9. Remember that we have counted 07 already. Thus, for two-digit numbers we have: numbers that contain a 7.
Three-digit numbers: Use the knowledge from the previous two scenarios: each hundred numbers will contain one 7 in numbers such as 107 or 507 and also 19 other sevens in numbers such as 271 or 237. Thus a total of 20 sevens per each hundred and 200 sevens for 1000. Since we have 700's within the range, that adds another 100 times that a seven will be written for a total of 300 times.

Kudos [?]: 41 [0], given: 1

Founder
Joined: 04 Dec 2002
Posts: 15585

Kudos [?]: 28499 [0], given: 5114

Location: United States (WA)
GMAT 1: 750 Q49 V42

### Show Tags

31 May 2010, 13:43
Please continue the discussion in the proper thread in the GMAT Club Tests Forum.

Don't be lazy - do a search.
_________________

Founder of GMAT Club

Just starting out with GMAT? Start here... or use our Daily Study Plan

Co-author of the GMAT Club tests

Kudos [?]: 28499 [0], given: 5114

Re: quant question   [#permalink] 31 May 2010, 13:43
Display posts from previous: Sort by

# quant question

Moderator: HiLine

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne 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®.