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

It is currently 23 Sep 2014, 18:30

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

What would be your approach to solve this problem

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
1 KUDOS received
Manager
Manager
avatar
Status: Only GMAT!!
Joined: 17 Sep 2010
Posts: 74
WE 1: 5.5+ years IT Prof.
Followers: 1

Kudos [?]: 8 [1] , given: 24

GMAT Tests User
What would be your approach to solve this problem [#permalink] New post 12 Jul 2011, 12:30
1
This post received
KUDOS
00:00
A
B
C
D
E

Difficulty:

(N/A)

Question Stats:

40% (03:56) correct 60% (00:21) wrong based on 5 sessions
How many integers "k" greater than 100 and less than 1000 are there such that if the hundreds and the units digits of "k" are reversed, the resulting integer is k+99?

A) 50
B) 60
C) 70
D) 80
E) 90
[Reveal] Spoiler: OA
Intern
Intern
avatar
Joined: 11 Sep 2010
Posts: 13
Location: India
GMAT 1: 620 Q49 V25
Followers: 0

Kudos [?]: 5 [0], given: 0

Re: What would be your approach to solve this problem [#permalink] New post 13 Jul 2011, 07:19
vivgmat wrote:
How many integers "k" greater than 100 and less than 1000 are there such that if the hundreds and the units digits of "k" are reversed, the resulting integer is k+99?

A) 50
B) 60
C) 70
D) 80
E) 90


Numbers will be like 102 => 201 = 102 + 99
203 => 302 = 103 + 99

so the hundereth digit and units digit are consecutive where unit digit is bigger than hundred digit.
There will be eight pairs of such numbers
for every pair there will 10 numbers like for 1&2 => 102, 112,132,142,152, 162,172,182,192.

Total = 8 *10 = 80 hence D.
2 KUDOS received
Manager
Manager
User avatar
Status: Trying to survive
Joined: 29 Jun 2011
Posts: 186
GMAt Status: Quant section
Concentration: Finance, Real Estate
Schools: WBS (D)
GMAT Date: 12-30-2011
GPA: 3.2
Followers: 10

Kudos [?]: 88 [2] , given: 94

GMAT Tests User
Re: What would be your approach to solve this problem [#permalink] New post 13 Jul 2011, 07:36
2
This post received
KUDOS
k=100x + 10y + z
99+k= 100z + 10y + x
thus 99+ 100x + 10y + z = 100z + 10y + x
99= 99z - 99x
so z = x+1
z must be no more than 8 , if it is 9 for example so x=10 and that impossible
so we have 8 possibility in each 100 and we have 10 hundreds in 1000
so 8*10= 80
you are welcome man :-D
please consider giving kudos
_________________

How can i lose my faith in life's fairness when i know that the dreams of those who sleep on the feathers are not more beautiful than the dreams of those who sleep on the ground? - Jubran Khaleel Jubran

3 KUDOS received
Math Forum Moderator
avatar
Joined: 20 Dec 2010
Posts: 2046
Followers: 128

Kudos [?]: 928 [3] , given: 376

GMAT Tests User
Re: What would be your approach to solve this problem [#permalink] New post 13 Jul 2011, 08:01
3
This post received
KUDOS
Silver89 wrote:
k=100x + 10y + z
99+k= 100z + 10y + x
thus 99+ 100x + 10y + z = 100z + 10y + x
99= 99z - 99x
so z = x+1
z must be no more than 8 , if it is 9 for example so x=10 and that impossible
so we have 8 possibility in each 100 and we have 10 hundreds in 1000
so 8*10= 80
you are welcome man :-D
please consider giving kudos


I solved it the same way;

If k=xyz

x+1=z
The numbers will be:

1@2 : "@" can be 0,1,2,3,4,5,6,7,8,9. Count=10
2@3 : "@" can be 0,1,2,3,4,5,6,7,8,9. Count=10
3@4 : "@" can be 0,1,2,3,4,5,6,7,8,9. Count=10
4@5
5@6
6@7
7@8
8@9 : "@" can be 0,1,2,3,4,5,6,7,8,9. Count=10

10*8=80

Ans: "D"
_________________

~fluke

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Manager
Manager
User avatar
Status: Trying to survive
Joined: 29 Jun 2011
Posts: 186
GMAt Status: Quant section
Concentration: Finance, Real Estate
Schools: WBS (D)
GMAT Date: 12-30-2011
GPA: 3.2
Followers: 10

Kudos [?]: 88 [0], given: 94

GMAT Tests User
Re: What would be your approach to solve this problem [#permalink] New post 13 Jul 2011, 08:06
hehe
nice solving approach fluke
and thanks for the kudos man
_________________

How can i lose my faith in life's fairness when i know that the dreams of those who sleep on the feathers are not more beautiful than the dreams of those who sleep on the ground? - Jubran Khaleel Jubran

Re: What would be your approach to solve this problem   [#permalink] 13 Jul 2011, 08:06
    Similar topics Author Replies Last post
Similar
Topics:
3 Tabular approach for solving Work problems nravi549 1 17 Oct 2010, 01:11
Specular problem, but different approach to solve them? rraggio 4 21 Sep 2010, 06:30
4 What's the secret to approaching this problem? lifeisshort 14 20 Aug 2010, 10:12
A Probability Approach For Solving Counting Problems KillerSquirrel 6 22 Sep 2007, 11:43
Solving problems in your head KillerSquirrel 4 14 Jul 2007, 04:01
Display posts from previous: Sort by

What would be your approach to solve this problem

  Question banks Downloads My Bookmarks Reviews Important topics  


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®.