Last visit was: 20 Nov 2025, 02:42 It is currently 20 Nov 2025, 02:42
Home
GMAT
Messages
Tests
Schools
Events
Rewards
Chat
My Profile
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
User avatar
swat
User avatar
Joined: 24 Sep 2009
Last visit: 29 Oct 2009
Posts: 14
Own Kudos:
42
Posts: 14
Kudos: 42
Q1. How many times does 3 appear in a number of 10 digits? 29 Sep 2009, 07:29
Kudos
Add Kudos
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
N
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions

History

Date
Time
Result
Not Attempted Yet
Q1. How many times does 3 appear in a number of 10 digits?
1/ Mean of the number is 3.8
2/ Range of the number is 1

Q2. A certain shell hold fewer than 50 books. What is the number of books?
1/ The books is divided into 3 groups of n books each and 2 books left
2/ The books is divided into m group of 7 books each and 2 books left



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 Data Sufficiency (DS) 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
TheRob
User avatar
Joined: 29 May 2008
Last visit: 11 Jun 2010
Posts: 86
Own Kudos:
898
Posts: 86
Kudos: 898
Q1. How many times does 3 appear in a number of 10 digits? 29 Sep 2009, 07:40
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Q2 is E too

From 1, it can be any multpile of three plus 2 < 50

From 2 It can be any multiple of 7 < 50

Together it can be multiple of 7 and 3 plus two < 50,
Ex. 23, 44
User avatar
swat
User avatar
Joined: 24 Sep 2009
Last visit: 29 Oct 2009
Posts: 14
Own Kudos:
42
Posts: 14
Kudos: 42
Q1. How many times does 3 appear in a number of 10 digits? 29 Sep 2009, 08:06
Kudos
Add Kudos
Bookmarks
Bookmark this Post
TheRob
Q1 is E
Show more

Could you give a little explanation, please...
Thank you.
User avatar
IanStewart
User avatar
GMAT Tutor
Joined: 24 Jun 2008
Last visit: 19 Nov 2025
Posts: 4,145
Own Kudos:
10,989
Given Kudos: 99
Expert
Expert reply
Posts: 4,145
Kudos: 10,989
Q1. How many times does 3 appear in a number of 10 digits? 29 Sep 2009, 10:04
Kudos
Add Kudos
Bookmarks
Bookmark this Post
swat
Q1. How many times does 3 appear in a number of 10 digits?
1/ Mean of the number is 3.8
2/ Range of the number is 1
Show more

These questions don't make any sense as they're written - where did you find them? There is no such thing as the "range of a number"; we only talk about the range of a set of numbers. If a set only contains a single number, its range is zero. I assume the question means to say "the mean of the number's digits is 3.8", and "the range of the number's digits is 1." If that's the intended meaning, the answer is C. Statement 1 simply tells us that the sum of the digits is 38, and there are several ways that can happen (one 2, nine 4s, for example, or two 3s and eight 4s). Statement 2 guarantees that we only have two different digits in our number, and they are consecutive integers. Taking both together, we must have digits which are above the mean and below the mean (they can't all be above average or below average), so our digits must be 3 and 4, since they are consecutive. Since they sum to 38, we must have eight 4s and two 3s.
User avatar
chandru42
User avatar
Joined: 21 May 2009
Last visit: 06 Feb 2023
Posts: 62
Own Kudos:
129
Given Kudos: 50
Posts: 62
Kudos: 129
Q1. How many times does 3 appear in a number of 10 digits? 29 Sep 2009, 19:20
Kudos
Add Kudos
Bookmarks
Bookmark this Post
answer is E to Q2
we get 2 values as answer
23 and 44
User avatar
dbw
User avatar
Joined: 30 Sep 2009
Last visit: 02 Oct 2009
Posts: 1
Posts: 1
Kudos: 0
Q1. How many times does 3 appear in a number of 10 digits? 30 Sep 2009, 03:15
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Pretty sure that Q1 is C,, though I reword the question as:

23. How many times does 3 appear in a 10 digit long number?
(1) The mean of the digits is 3.8
(2) The range of the digits is 1

Which could be a real GMAT question... ;)


I'll start with Statement 2, since Statement 1 is confusing. :-D If the range of the digits is 1, even if 3 appears in the # at all, it 3 & 4 or 2 & 3, as many of each as you would like.

Answers ACE remain.

Let's check C. If the range is 1 and the mean is 3.8 (i.e. the sum of the digits is 38), all digits must be either 3 or 4. It is simple to show that there must then be eight 4's and two 3's.

Answers AC remain.

Let's check statement 1 alone. If we don't know the range, could we still get a sum of 38? of course. seven 4's, a 5 a 3 and a 2 will do just as well. (I just added 1 to one of the 4's and subtracted 1 from one of the 3's. I'm lazy)

So I get C.


p.s. GMAT would probably write question 2 as:
24. A certain shelf holds fewer than 50 books. How many books does it hold?
(1) If the books are divided into 3 groups of n books each, there will be 2 books left
(2) If the books are divided into m group of 7 books each, there will be 2 books left



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 Data Sufficiency (DS) 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!
Moderators:
Bunuel
Math Expert
105408 posts
GMATBusters
GMAT Tutor
1924 posts