GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 19 Apr 2019, 07:35

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

The difference between a two-digit number and the number obtained by r

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

Hide Tags

 
Manager
Manager
avatar
G
Status: Manager
Joined: 02 Nov 2018
Posts: 175
Location: Bangladesh
GMAT ToolKit User CAT Tests
The difference between a two-digit number and the number obtained by r  [#permalink]

Show Tags

New post 19 Mar 2019, 07:06
1
00:00
A
B
C
D
E

Difficulty:

  65% (hard)

Question Stats:

54% (02:53) correct 46% (03:08) wrong based on 26 sessions

HideShow timer Statistics

The difference between a two-digit number and the number obtained by revers-ing its digits is 5 times the sum of the digits of either number. What is the sum of the two digit number and its reverse?

(A) 44

(B) 55

(C) 77

(D) 99

(E) 110

_________________
Give a kudos if u find my post helpful. kudos motivates active discussions :)

CEO
CEO
User avatar
D
Status: GMATINSIGHT Tutor
Joined: 08 Jul 2010
Posts: 2906
Location: India
GMAT: INSIGHT
Schools: Darden '21
WE: Education (Education)
Reviews Badge
Re: The difference between a two-digit number and the number obtained by r  [#permalink]

Show Tags

New post 19 Mar 2019, 08:18
Noshad wrote:
The difference between a two-digit number and the number obtained by revers-ing its digits is 5 times the sum of the digits of either number. What is the sum of the two digit number and its reverse?

(A) 44

(B) 55

(C) 77

(D) 99

(E) 110


Let, Number = ab = 10a+b
Number after reversing digits = ba = 10b+a


(10a+b)-(10b+a) = 5*(a+b)

i.e. 9a - 9b = 5a + 5b

i.e. 9(a-b) = 5(a+b)

which is possible only when a+b = 9 and a-b = 5
i.e. a = 7 and b = 2

Requires sum = 72+27 = 99

Answer: Option D
_________________
Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

ACCESS FREE GMAT TESTS HERE:22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION
VP
VP
avatar
P
Joined: 07 Dec 2014
Posts: 1179
Re: The difference between a two-digit number and the number obtained by r  [#permalink]

Show Tags

New post 19 Mar 2019, 10:47
Noshad wrote:
The difference between a two-digit number and the number obtained by revers-ing its digits is 5 times the sum of the digits of either number. What is the sum of the two digit number and its reverse?

(A) 44

(B) 55

(C) 77

(D) 99

(E) 110


we know that the difference between any two digit reversals xy and yx will be 9(x-y)
so 9(x-y)=5(x+y)→
x/y=7/2
72+27=99
D
Manager
Manager
User avatar
B
Joined: 11 Feb 2013
Posts: 68
Location: Bangladesh
GMAT 1: 490 Q44 V15
GMAT 2: 690 Q47 V38
GPA: 3.05
WE: Analyst (Commercial Banking)
GMAT ToolKit User Reviews Badge
Re: The difference between a two-digit number and the number obtained by r  [#permalink]

Show Tags

New post 19 Mar 2019, 11:16
1
The difference of the two digit number itself and it's reversal is always divisible by 9.
And the resulting number = 9(larger digit- smaller digit)
For example, difference between 18 and 81 = 9(8-1)=63.


The summation of the two digit number itself and it's reversal is always divisible by 11. And the resulting number = 11(larger digit+smaller digit)
For example, difference between 18 and 81 = 11(8+1)=99.

Posted from my mobile device
CEO
CEO
User avatar
P
Joined: 18 Aug 2017
Posts: 2998
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
GMAT ToolKit User Premium Member CAT Tests
Re: The difference between a two-digit number and the number obtained by r  [#permalink]

Show Tags

New post 19 Mar 2019, 11:32
Noshad wrote:
The difference between a two-digit number and the number obtained by revers-ing its digits is 5 times the sum of the digits of either number. What is the sum of the two digit number and its reverse?

(A) 44

(B) 55

(C) 77

(D) 99

(E) 110


given
10a+b-10b-a= 5a+5b
we get
2a=7b
a= 7 ; b = 2
so sum = 99
IMO D
_________________
If you liked my solution then please give Kudos. Kudos encourage active discussions.
GMAT Club Bot
Re: The difference between a two-digit number and the number obtained by r   [#permalink] 19 Mar 2019, 11:32
Display posts from previous: Sort by

The difference between a two-digit number and the number obtained by r

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


cron
Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| 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®.