It is currently 20 Nov 2017, 14:47

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

What is the tens digit of the positive integer n ?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

4 KUDOS received
Verbal Forum Moderator
User avatar
D
Status: Greatness begins beyond your comfort zone
Joined: 08 Dec 2013
Posts: 1597

Kudos [?]: 1005 [4], given: 80

Location: India
Concentration: General Management, Strategy
GPA: 3.2
WE: Information Technology (Consulting)
GMAT ToolKit User Reviews Badge CAT Tests
What is the tens digit of the positive integer n ? [#permalink]

Show Tags

New post 19 Jun 2016, 10:33
4
This post received
KUDOS
3
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

61% (00:39) correct 39% (01:01) wrong based on 259 sessions

HideShow timer Statistics

What is the tens digit of the positive integer n ?

1. The hundreds digit of 10n is 2 .

2. The tens digit of n-9 is 1 .
[Reveal] Spoiler: OA

_________________

When everything seems to be going against you, remember that the airplane takes off against the wind, not with it. - Henry Ford
The Moment You Think About Giving Up, Think Of The Reason Why You Held On So Long
+1 Kudos if you find this post helpful

Kudos [?]: 1005 [4], given: 80

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 42269

Kudos [?]: 132827 [0], given: 12378

Re: What is the tens digit of the positive integer n ? [#permalink]

Show Tags

New post 19 Jun 2016, 10:35
Skywalker18 wrote:
What is the tens digit of the positive integer n ?

1. The hundreds digit of 10n is 2 .

2. The tens digit of n-9 is 1 .


Very similar question from OG for additional practice: if-n-is-a-positive-integer-what-is-the-tens-digit-of-n-144725.html
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

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?
Extra-hard Quant Tests with Brilliant Analytics

Kudos [?]: 132827 [0], given: 12378

Senior Manager
Senior Manager
avatar
Joined: 02 Dec 2014
Posts: 369

Kudos [?]: 92 [0], given: 349

Location: Russian Federation
Concentration: General Management, Economics
GMAT 1: 640 Q44 V33
WE: Sales (Telecommunications)
What is the tens digit of the positive integer n ? [#permalink]

Show Tags

New post 19 Jun 2016, 11:43
Skywalker18 wrote:
What is the tens digit of the positive integer n ?

1. The hundreds digit of 10n is 2 .

2. The tens digit of n-9 is 1 .


Statement 1. This means that n can be 20 or 21 or 22 and so on and then tens digit is 2 always. Sufficient
Statement 2. n can be 20 or 28 or 120. Hence sufficient.
Answer D. Wait for official answer
_________________

"Are you gangsters?" - "No we are Russians!"

Kudos [?]: 92 [0], given: 349

1 KUDOS received
Senior Manager
Senior Manager
avatar
Joined: 02 Mar 2012
Posts: 360

Kudos [?]: 91 [1], given: 4

Schools: Schulich '16
Re: What is the tens digit of the positive integer n ? [#permalink]

Show Tags

New post 20 Jun 2016, 05:28
1
This post received
KUDOS
1
This post was
BOOKMARKED
Konstantin1983 wrote:
Skywalker18 wrote:
What is the tens digit of the positive integer n ?

1. The hundreds digit of 10n is 2 .

2. The tens digit of n-9 is 1 .


Statement 1. This means that n can be 20 or 21 or 22 and so on and then tens digit is 2 always. Sufficient
Statement 2. n can be 20 or 28 or 120. Hence sufficient.
Answer D. Wait for official answer


A for me

what about 19? 19-9=10 :)

Kudos [?]: 91 [1], given: 4

Manager
Manager
avatar
S
Joined: 04 Apr 2015
Posts: 101

Kudos [?]: 26 [0], given: 3959

Re: What is the tens digit of the positive integer n ? [#permalink]

Show Tags

New post 20 Jun 2016, 10:16
IMO A

since 19-9 will have tens as 1
and 28-9 will have 1

Kudos [?]: 26 [0], given: 3959

Intern
Intern
avatar
Joined: 04 Nov 2015
Posts: 3

Kudos [?]: [0], given: 26

Re: What is the tens digit of the positive integer n ? [#permalink]

Show Tags

New post 22 Jun 2016, 07:49
1. The hundreds digit of 10n is 2 .
Tens digit will be 2 .
Sufficient

2. The tens digit of n-9 is 1 .
Not Sufficient

Answer A

Kudos [?]: [0], given: 26

Manager
Manager
User avatar
B
Joined: 16 Mar 2016
Posts: 135

Kudos [?]: 43 [0], given: 0

Location: France
GMAT 1: 660 Q47 V33
GPA: 3.25
GMAT ToolKit User
Re: What is the tens digit of the positive integer n ? [#permalink]

Show Tags

New post 22 Jun 2016, 13:36
let's write n=ABCD, where D units digit, C tens, D hundreds, etc.
We need to know C

(1) The hundreds digit of 10n is 2
10*n = ABCD0
So, hundreds' digit is C = 2
Sufficient

(2) The tens digit of n-9 is 1
19-9 = 10
20-9 = 11
Not sufficient

Kudos [?]: 43 [0], given: 0

Expert Post
Math Revolution GMAT Instructor
User avatar
P
Joined: 16 Aug 2015
Posts: 4326

Kudos [?]: 3041 [0], given: 0

GPA: 3.82
Premium Member CAT Tests
Re: What is the tens digit of the positive integer n ? [#permalink]

Show Tags

New post 22 Jun 2016, 21:14
Expert's post
2
This post was
BOOKMARKED
There is 1 variable (n) in the original condition. In order to match the number of variables and the number of equations, we need 1 equation. Since the condition 1) and 2) each has 1 equation, there is high chance that D is the correct answer.
In case of the condition 1), the tens-digit of n is always 2. The answer is unique and the condition is sufficient.
In case of the condition 2), from n=19 and 21, the tens-digit is 1 and 2. Hence, the answer is not unique and the condition is not sufficient. Thus, the correct answer is A.

 For cases where we need 1 more equation, such as original conditions with “1 variable”, or “2 variables and 1 equation”, or “3 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 59 % chance that D is the answer, while A or B has 38% chance and C or E has 3% chance. Since D is most likely to be the answer using 1) and 2) separately according to DS definition. Obviously there may be cases where the answer is A, B, C or E.
Attachments

variable approach's answer probability.jpg
variable approach's answer probability.jpg [ 219.74 KiB | Viewed 3122 times ]


_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
Find a 10% off coupon code for GMAT Club members.
“Receive 5 Math Questions & Solutions Daily”
Unlimited Access to over 120 free video lessons - try it yourself
See our Youtube demo

Kudos [?]: 3041 [0], given: 0

1 KUDOS received
Senior Manager
Senior Manager
User avatar
Joined: 18 Jan 2010
Posts: 257

Kudos [?]: 159 [1], given: 9

Re: What is the tens digit of the positive integer n ? [#permalink]

Show Tags

New post 22 Jun 2016, 22:38
1
This post received
KUDOS
2
This post was
BOOKMARKED
Skywalker18 wrote:
What is the tens digit of the positive integer n ?

1. The hundreds digit of 10n is 2 .

2. The tens digit of n-9 is 1 .


Statement 1

say n = 325. Ten's digit is 2.

10n = 3250. Here Hundred's digit is 2.

again say n = 25, Ten's digit is 2.

10n = 250. Here Hundred's digit is 2.

We will see that always we will get unique answer.

Statement 1 is sufficient.

Statement 2

say n = 19, then 19-9 = 10. ten's digit of 10 is 1. ten's digit of 19 is also 1

now say n = 22, then 22-9 = 13. ten's digit of 13 is 1. BUT ten's digit of 22 is NOT 1. It is 2.

So not sufficient.

A is the answer.

Kudos [?]: 159 [1], given: 9

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 15613

Kudos [?]: 283 [0], given: 0

Premium Member
Re: What is the tens digit of the positive integer n ? [#permalink]

Show Tags

New post 22 Oct 2017, 04:51
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.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Kudos [?]: 283 [0], given: 0

Re: What is the tens digit of the positive integer n ?   [#permalink] 22 Oct 2017, 04:51
Display posts from previous: Sort by

What is the tens digit of the positive integer n ?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

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®.