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

It is currently 14 Dec 2018, 16:08

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 in December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
  • Typical Day of a UCLA MBA Student - Recording of Webinar with UCLA Adcom and Student

     December 14, 2018

     December 14, 2018

     10:00 PM PST

     11:00 PM PST

    Carolyn and Brett - nicely explained what is the typical day of a UCLA student. I am posting below recording of the webinar for those who could't attend this session.
  • Free GMAT Strategy Webinar

     December 15, 2018

     December 15, 2018

     07:00 AM PST

     09:00 AM PST

    Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

If 7(a – 1) = 17(b – 1), and a and b are both positive integers the pr

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

Hide Tags

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 51215
If 7(a – 1) = 17(b – 1), and a and b are both positive integers the pr  [#permalink]

Show Tags

New post 19 Nov 2018, 23:17
00:00
A
B
C
D
E

Difficulty:

  85% (hard)

Question Stats:

47% (02:03) correct 53% (02:12) wrong based on 133 sessions

HideShow timer Statistics

If 7(a – 1) = 17(b – 1), and a and b are both positive integers the product of which is greater than 1, then what is the least possible sum of a and b?

A. 2
B. 7
C. 17
D. 24
E. 26

_________________

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

Most Helpful Community Reply
Director
Director
User avatar
P
Joined: 31 Oct 2013
Posts: 881
Concentration: Accounting, Finance
GPA: 3.68
WE: Analyst (Accounting)
If 7(a – 1) = 17(b – 1), and a and b are both positive integers the pr  [#permalink]

Show Tags

New post Updated on: 01 Dec 2018, 16:17
6
Bunuel wrote:
If 7(a – 1) = 17(b – 1), and a and b are both positive integers the product of which is greater than 1, then what is the least possible sum of a and b?

A. 2
B. 7
C. 17
D. 24
E. 26



7(a-1) =17(b-1)

17 is not divisible by 7. thus b-1 must be divisible by 7. So, b - 1 = 7k . least value of b= 8.

on the other hand, 7 is not divisible by 17. (a -1 ) is must be the multiple of 17. so least value of a = 18.


least value of a + b = 18 + 8 = 26.

E is our answer.

Originally posted by selim on 20 Nov 2018, 00:47.
Last edited by selim on 01 Dec 2018, 16:17, edited 1 time in total.
General Discussion
Manager
Manager
User avatar
G
Joined: 13 Jan 2018
Posts: 128
Location: India
GMAT 1: 580 Q47 V23
GPA: 4
Reviews Badge
Re: If 7(a – 1) = 17(b – 1), and a and b are both positive integers the pr  [#permalink]

Show Tags

New post 19 Nov 2018, 23:42
2
\(7a + 10 = 17b\)

Least possible value apart from (1,1) is (18,8)

\(7(18) + 10 = 17(8)\)

So a+b = 26.

OPTION: E
_________________

____________________________
Regards,

Chaitanya



+1 Kudos

if you like my explanation!!!

Manager
Manager
avatar
S
Joined: 21 Jun 2017
Posts: 157
Concentration: Finance, Economics
WE: Corporate Finance (Commercial Banking)
CAT Tests
Re: If 7(a – 1) = 17(b – 1), and a and b are both positive integers the pr  [#permalink]

Show Tags

New post 20 Nov 2018, 04:55
1
eswarchethu135 wrote:
\(7a + 10 = 17b\)

Least possible value apart from (1,1) is (18,8)

\(7(18) + 10 = 17(8)\)

So a+b = 26.

OPTION: E

Hi eswarchethu135
How did you get 18 , 8 in one step. Is that any shortcut ? Please explain.
_________________

Even if it takes me 30 attempts, I am determined enough to score 740+ in my 31st attempt. This is it, this is what I have been waiting for, now is the time to get up and fight, for my life is 100% my responsibility.

Manager
Manager
User avatar
G
Joined: 13 Jan 2018
Posts: 128
Location: India
GMAT 1: 580 Q47 V23
GPA: 4
Reviews Badge
Re: If 7(a – 1) = 17(b – 1), and a and b are both positive integers the pr  [#permalink]

Show Tags

New post 20 Nov 2018, 04:58
Haha! I just plugged in numbers. I kept on going from 1 to 8 multiplying with 17 and checking for divisibility by 7 after subtracting 10 from the product. It took me 45 seconds to verify from 1 to 8. I think this time is not a big deal in GMAT.

Posted from my mobile device
_________________

____________________________
Regards,

Chaitanya



+1 Kudos

if you like my explanation!!!

Intern
Intern
avatar
B
Joined: 22 Sep 2018
Posts: 19
Re: If 7(a – 1) = 17(b – 1), and a and b are both positive integers the pr  [#permalink]

Show Tags

New post 27 Nov 2018, 00:15
1
Bunuel wrote:
If 7(a – 1) = 17(b – 1), and a and b are both positive integers the product of which is greater than 1, then what is the least possible sum of a and b?

A. 2
B. 7
C. 17
D. 24
E. 26


Since both 7 and 17 are prime numbers, take LCM of 7 and 17,i.e. 119.
For both RHS and LHS to be minimum 119, (a-1) must take the value of 17. Thus, a can be a minimum of 18.
By this logic,(b-1) must take minimum value of 7. So b has to be 8.
Thus, a+b=18+8=26.

Hope this helps.
Director
Director
avatar
P
Joined: 31 Jul 2017
Posts: 504
Location: Malaysia
Schools: INSEAD Jan '19
GMAT 1: 700 Q50 V33
GPA: 3.95
WE: Consulting (Energy and Utilities)
Re: If 7(a – 1) = 17(b – 1), and a and b are both positive integers the pr  [#permalink]

Show Tags

New post 27 Nov 2018, 00:24
Bunuel wrote:
If 7(a – 1) = 17(b – 1), and a and b are both positive integers the product of which is greater than 1, then what is the least possible sum of a and b?

A. 2
B. 7
C. 17
D. 24
E. 26


\(a - 1= \frac{17(b – 1)}{7}\)

As a is an Integer, b =8. Hence, a = 18.

a+b = 26.
_________________

If my Post helps you in Gaining Knowledge, Help me with KUDOS.. !!

Intern
Intern
avatar
B
Joined: 05 Jun 2018
Posts: 7
Location: India
Concentration: General Management, Leadership
WE: Consulting (Computer Software)
Re: If 7(a – 1) = 17(b – 1), and a and b are both positive integers the pr  [#permalink]

Show Tags

New post 30 Nov 2018, 07:33
Two numbers are equal if the expression on each side is equal to the given number on opposite side.
For e.g:

7(a-1)=17(b-1)

so,
a-1=17
b-1=7

Hence, a=18
b=8
GMAT Club Bot
Re: If 7(a – 1) = 17(b – 1), and a and b are both positive integers the pr &nbs [#permalink] 30 Nov 2018, 07:33
Display posts from previous: Sort by

If 7(a – 1) = 17(b – 1), and a and b are both positive integers the pr

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


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®.