Find all School-related info fast with the new School-Specific MBA Forum

It is currently 23 Oct 2014, 08:05

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

A three-digit number k, the units digit is non-zero, what is

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Director
Director
avatar
Joined: 15 Aug 2005
Posts: 804
Location: Singapore
Followers: 2

Kudos [?]: 7 [0], given: 0

A three-digit number k, the units digit is non-zero, what is [#permalink] New post 05 Oct 2005, 02:03
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
A three-digit number k, the units digit is non-zero, what is the tens digit?

(1) The tens digit of k+9 is 3.
(2) The tens digit of k+4 is 2.
_________________

Cheers, Rahul.

Senior Manager
Senior Manager
avatar
Joined: 22 Jun 2005
Posts: 364
Location: London
Followers: 1

Kudos [?]: 4 [0], given: 0

 [#permalink] New post 05 Oct 2005, 03:08
I'd pick A.

1, sufficient, we know that the unit digits is non-zero.
So, the tens digit has to be 2. Just pick some numbers here.

unit digit = 1, T=Tens digit.
9
+T1
-------
30

9
+T9
-------
30
T has to be 2

2, insufficient, two values for T

4
+T1
-------
25 -> T is 2

4
+T9
-------
23 -> T is 1

hmm...The numbers 9 and 4 in the above examples should be straight above the unit digits. :)

Last edited by macca on 05 Oct 2005, 03:10, edited 1 time in total.
SVP
SVP
avatar
Joined: 14 Dec 2004
Posts: 1709
Followers: 1

Kudos [?]: 37 [0], given: 0

 [#permalink] New post 05 Oct 2005, 03:10
I also got 'A' but what if 'k' is negative....???
Senior Manager
Senior Manager
avatar
Joined: 22 Jun 2005
Posts: 364
Location: London
Followers: 1

Kudos [?]: 4 [0], given: 0

 [#permalink] New post 05 Oct 2005, 03:29
Vivek!

I think you're right. k could be negative. It's not stated that k is positive.
And the answer is probably E in that case.

1,
if k > 0 -> tens digit = 2
if k< 0 -> tens digit = 4 or 3

2,
if k>0 -> tens digit = 2 or 1
if k<0 -> tens digit = 3,2

Both together, -> insufficient
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jul 2004
Posts: 5095
Location: Singapore
Followers: 19

Kudos [?]: 155 [0], given: 0

 [#permalink] New post 05 Oct 2005, 04:10
From statement 1, we know that the tens digit of K+9 is 3. However, we're also told that the last digit of k is non-zero. So the last digit cannot be 1.

If the units digit is from 2-9, if we add 9, we will have a carry over of 1 to the tens digit position. In order to get 3 in the tens position, the original number must be holding a 2 in the tens position.

Statement 1 is therefore sufficient.

From statement 2, we know the tens digit of K+4 is 2. However, we're also told the last digit of k is non-zero, so the last digit cannot be 6. It can be 1-5, 7-9. If the units digit is 1-5, the tens digit is 2. If the units digit is 7-9, the units digit is 1. Since we have two possible solutions, Statement 2 is not sufficient.

Ans: A.
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jul 2004
Posts: 5095
Location: Singapore
Followers: 19

Kudos [?]: 155 [0], given: 0

 [#permalink] New post 05 Oct 2005, 04:11
macca wrote:
Vivek!

I think you're right. k could be negative. It's not stated that k is positive.
And the answer is probably E in that case.

1,
if k > 0 -> tens digit = 2
if k< 0 -> tens digit = 4 or 3

2,
if k>0 -> tens digit = 2 or 1
if k<0 -> tens digit = 3,2

Both together, -> insufficient


oops :oops: Did not consider the negative case.
Director
Director
avatar
Joined: 15 Aug 2005
Posts: 804
Location: Singapore
Followers: 2

Kudos [?]: 7 [0], given: 0

 [#permalink] New post 05 Oct 2005, 05:06
Thanks for the expln. guys. ywilfred, your reasoning makes it very easy to understand.
Well the OA is strangely A. Strangely coz vivek makes a valid point!!
_________________

Cheers, Rahul.

Manager
Manager
avatar
Joined: 28 Jun 2005
Posts: 68
Location: New York, NY
Followers: 1

Kudos [?]: 2 [0], given: 0

 [#permalink] New post 05 Oct 2005, 06:52
I would have chosen A as well because I did not think about the possibility of k being negative. How do you prevent yourself from overanalyzing a question like this? The negative case is a valid point...
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jul 2004
Posts: 5095
Location: Singapore
Followers: 19

Kudos [?]: 155 [0], given: 0

 [#permalink] New post 05 Oct 2005, 06:57
rahulraao wrote:
Thanks for the expln. guys. ywilfred, your reasoning makes it very easy to understand.
Well the OA is strangely A. Strangely coz vivek makes a valid point!!


Just out of curiosity, what is the source of this question? I doubt the OG would allow you to second guess the nature of the question (in this case, we're left wondering if the 3 digit number could be negative) :wink:
Director
Director
avatar
Joined: 15 Aug 2005
Posts: 804
Location: Singapore
Followers: 2

Kudos [?]: 7 [0], given: 0

 [#permalink] New post 05 Oct 2005, 17:07
This is a question from Math Test 3 0r 4 from Scoretop.com's free online tests.
_________________

Cheers, Rahul.

Director
Director
avatar
Joined: 23 Jun 2005
Posts: 847
GMAT 1: 740 Q48 V42
Followers: 5

Kudos [?]: 25 [0], given: 1

 [#permalink] New post 05 Oct 2005, 17:14
I got it as A too!
So, being wrong sometimes has its advantages too... or am I wrong? :lol:
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jul 2004
Posts: 5095
Location: Singapore
Followers: 19

Kudos [?]: 155 [0], given: 0

 [#permalink] New post 05 Oct 2005, 17:17
anandsebastin wrote:
I got it as A too!
So, being wrong sometimes has its advantages too... or am I wrong? :lol:


A is the OA given for this question. The only question was whether the 3 digit number can be negative, that's all. But I suppose ETS or Pearson will set questions that does not leave you in any doubt. :wink:
VP
VP
avatar
Joined: 22 Aug 2005
Posts: 1128
Location: CA
Followers: 1

Kudos [?]: 32 [0], given: 0

 [#permalink] New post 05 Oct 2005, 17:19
MsStephanie wrote:
I would have chosen A as well because I did not think about the possibility of k being negative. How do you prevent yourself from overanalyzing a question like this? The negative case is a valid point...


I have exactly same question as you. I hope real test will not have questions with open scope.
SVP
SVP
avatar
Joined: 14 Dec 2004
Posts: 1709
Followers: 1

Kudos [?]: 37 [0], given: 0

 [#permalink] New post 05 Oct 2005, 20:28
rahul, macca, MsStephanie, anand, duttsit....

ywilfred has a point.
So far, I have not seen any question by ETS (in OG or any other source) having any doubtful answer but at the same time I have seen couple of controversial questions in other non-ETS material. I think we should be careful, not to take our mistakes too seriously in such a material, just learn & move ahead...
SVP
SVP
avatar
Joined: 14 Dec 2004
Posts: 1709
Followers: 1

Kudos [?]: 37 [0], given: 0

 [#permalink] New post 05 Oct 2005, 20:43
Ok.

Just wanted to put one of my learnings...
Whenever there is a DS question, which just says "a number",

Don't forget to check,

1) Can it be an integer
2) Can it be a floating ppoint number (or a fraction)
3) Can it be a zero (sometimes I made mistakes by ignoring it to be a zero)

& in each of 1) & 2) above,

a) can it be a negative (integer/float)
b) can it be a positive (integer/float)
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 07 Jul 2004
Posts: 5095
Location: Singapore
Followers: 19

Kudos [?]: 155 [0], given: 0

 [#permalink] New post 05 Oct 2005, 20:53
vivek123 wrote:
Ok.

Just wanted to put one of my learnings...
Whenever there is a DS question, which just says "a number",

Don't forget to check,

1) Can it be an integer
2) Can it be a floating ppoint number (or a fraction)
3) Can it be a zero (sometimes I made mistakes by ignoring it to be a zero)

& in each of 1) & 2) above,

a) can it be a negative (integer/float)
b) can it be a positive (integer/float)


Good roundup, Vivek.... and floating point number.. hmm.. computer engineering? :wink:
SVP
SVP
avatar
Joined: 14 Dec 2004
Posts: 1709
Followers: 1

Kudos [?]: 37 [0], given: 0

 [#permalink] New post 06 Oct 2005, 20:15
:-D ha ha ha... yeah! I'm a computer bug!
Director
Director
avatar
Joined: 15 Aug 2005
Posts: 804
Location: Singapore
Followers: 2

Kudos [?]: 7 [0], given: 0

 [#permalink] New post 08 Oct 2005, 03:25
Oh my god!! What in good heavens is a floating point number??? :oops:

This forum can indeed be intimidating sometimes! :wink:
_________________

Cheers, Rahul.

  [#permalink] 08 Oct 2005, 03:25
    Similar topics Author Replies Last post
Similar
Topics:
5 Experts publish their posts in the topic If the units digit of the three-digit positive integer k is KocharRohit 6 17 Oct 2009, 19:28
If the units digit of the three-digit positive integer k shinewine 3 26 Aug 2006, 06:45
A three-digit number k, the units digit is non-zero mand-y 6 24 Jul 2006, 10:51
A three-digit number k, the units digit is non-zero, what is sudhagar 9 11 Oct 2005, 08:37
If the units digit of the three-digit positive integer k is mbassmbass04 1 01 Oct 2005, 15:28
Display posts from previous: Sort by

A three-digit number k, the units digit is non-zero, what is

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

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

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®.