Last visit was: 26 Apr 2024, 00:09 It is currently 26 Apr 2024, 00:09

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.
Close
Request Expert Reply
Confirm Cancel
User avatar
Manager
Manager
Joined: 19 Aug 2009
Posts: 72
Own Kudos [?]: 961 [1]
Given Kudos: 46
Send PM
User avatar
VP
VP
Joined: 29 Aug 2007
Posts: 1021
Own Kudos [?]: 1726 [1]
Given Kudos: 19
Send PM
User avatar
Manager
Manager
Joined: 22 Sep 2009
Posts: 151
Own Kudos [?]: 30 [2]
Given Kudos: 8
Location: Tokyo, Japan
Send PM
User avatar
Retired Moderator
Joined: 20 Dec 2010
Posts: 1114
Own Kudos [?]: 4702 [1]
Given Kudos: 376
Send PM
Re: Find the 28383rd term of series 123456789101112..... [#permalink]
1
Kudos
Digit to be found: "28383"

One digit numbers: 9*1=9 digits
Two digit numbers: 90*2=180 digits
Three digit numbers: 900*3=2700 digits
Four digit numbers: 9000*4=36000 > more than 28383. So the digit got to be from a number less than a 5 digit numbers.

Digits used until the number 999: 9+180+2700 = 2889
Digit to be found: 28383
or
28383-2889 = 25494 digit from the first digit i.e. "1" of the number (1000)

Dividing it by 4 will give us the number's index in four digit numbers: 6373. Remainder 2.

"6373" numbers are fully utilized after 999.

999+6373 = 7372

Next number: 7373

The digit will be the second digit(Remainder: 2) of the number 7373.

Ans: "A"

Took almost 4 minutes to formulate and solve this. Yet, I am not too confident about its correctness.

Perhaps there is a better way to solve!!!
Tutor
Joined: 16 Oct 2010
Posts: 14823
Own Kudos [?]: 64926 [0]
Given Kudos: 426
Location: Pune, India
Send PM
Re: Find the 28383rd term of series 123456789101112..... [#permalink]
Expert Reply
fluke wrote:
Digit to be found: "28383"

One digit numbers: 9*1=9 digits
Two digit numbers: 90*2=180 digits
Three digit numbers: 900*3=2700 digits
Four digit numbers: 9000*4=36000 > more than 28383. So the digit got to be from a number less than a 5 digit numbers.

Digits used until the number 999: 9+180+2700 = 2889
Digit to be found: 28383
or
28383-2889 = 25494 digit from the first digit i.e. "1" of the number (1000)

Dividing it by 4 will give us the number's index in four digit numbers: 6373. Remainder 2.

"6373" numbers are fully utilized after 999.

999+6373 = 7372

Next number: 7373

The digit will be the second digit(Remainder: 2) of the number 7373.

Ans: "A"

Took almost 4 minutes to formulate and solve this. Yet, I am not too confident about its correctness.

Perhaps there is a better way to solve!!!


Not a realistic GMAT question. Too many painful additions and subtractions. You will not find any question in OG that involves too many calculations. Even if it seems you need to calculate a lot in some questions, it will just be because you haven't seen a trick. Also, the question is kind of direct and straightforward. Terribly lacks the 'oomph' factor that tougher GMAT questions have. (If you like Math, you will end up enjoying your GMAT Quant section, whether you score well in it or not.)
User avatar
Non-Human User
Joined: 09 Sep 2013
Posts: 32680
Own Kudos [?]: 822 [0]
Given Kudos: 0
Send PM
Re: Find the 28383rd term of series 123456789101112..... [#permalink]
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.

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
Re: Find the 28383rd term of series 123456789101112..... [#permalink]
Moderators:
Math Expert
92915 posts
Senior Moderator - Masters Forum
3137 posts

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