It is currently 18 Oct 2017, 06:41

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

If a, b, and c are positive integers, is (a+b)c divisible by 3? 1) 2-

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

Hide Tags

Expert Post
1 KUDOS received
Math Revolution GMAT Instructor
User avatar
P
Joined: 16 Aug 2015
Posts: 4127

Kudos [?]: 2886 [1], given: 0

GPA: 3.82
Premium Member CAT Tests
If a, b, and c are positive integers, is (a+b)c divisible by 3? 1) 2- [#permalink]

Show Tags

New post 03 Aug 2017, 01:26
1
This post received
KUDOS
Expert's post
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

57% (00:45) correct 43% (00:51) wrong based on 69 sessions

HideShow timer Statistics

If a, b, and c are positive integers, is (a+b)c divisible by 3?

1) 2-digit integer ab is divisible by 3.
2) When c is divided by 3, the remainder is 0.
[Reveal] Spoiler: OA

_________________

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 [?]: 2886 [1], given: 0

Intern
Intern
avatar
B
Joined: 31 Jan 2017
Posts: 41

Kudos [?]: 1 [0], given: 162

Re: If a, b, and c are positive integers, is (a+b)c divisible by 3? 1) 2- [#permalink]

Show Tags

New post 03 Aug 2017, 02:44
Statement 1: let a=3 and b=2 then ab=6 which is divisble by 3 then putting the value in the eq we get 5c which is not divisible by 3 so no
put a=3 and b=3 then ab is divisible by 3 and also 6c which is divisible by 3 so yes
Insufficient

Statement 2: since c is divisible by 3 therefore (a+b)c is also divisible by 3
Sufficient

Ans: B

Sent from my SM-J210F using GMAT Club Forum mobile app

Kudos [?]: 1 [0], given: 162

Intern
Intern
avatar
B
Joined: 03 Apr 2016
Posts: 1

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

Location: United States (TX)
GMAT 1: 740 Q49 V42
GPA: 3.58
Re: If a, b, and c are positive integers, is (a+b)c divisible by 3? 1) 2- [#permalink]

Show Tags

New post 03 Aug 2017, 09:09
Is "two digit integer ab" supposed to reflect a number where a is the tens digit, and b the ones digit? Or does it mean the product of a and b?

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

Intern
Intern
avatar
B
Joined: 21 Jun 2017
Posts: 10

Kudos [?]: 2 [0], given: 69

GMAT 1: 750 Q50 V41
Re: If a, b, and c are positive integers, is (a+b)c divisible by 3? 1) 2- [#permalink]

Show Tags

New post 03 Aug 2017, 10:49
Statement 1: ab = 10a+b = (a+b)+9a is divisible by 3 so a+b is divisible by 3
Statement 2: Obvious yes

Kudos [?]: 2 [0], given: 69

Expert Post
Math Revolution GMAT Instructor
User avatar
P
Joined: 16 Aug 2015
Posts: 4127

Kudos [?]: 2886 [0], given: 0

GPA: 3.82
Premium Member CAT Tests
Re: If a, b, and c are positive integers, is (a+b)c divisible by 3? 1) 2- [#permalink]

Show Tags

New post 06 Aug 2017, 18:13
==> If you modify the original condition and the question, in order to have (a+b)c to be divided by 3, a+b or c has to be divided by 3. However, if you look at con 2), c is divisible by 3, hence it is yes and sufficient. For con 1), ab is also divisible by 3, and thus a+b is also divisible by 3, hence it is yes and sufficient.
Therefore, the answer is D. This type of question is a 5051-level question which applies CMT 4 (B: if you get A or B too easily, consider D).

Answer: D
_________________

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 [?]: 2886 [0], given: 0

Re: If a, b, and c are positive integers, is (a+b)c divisible by 3? 1) 2-   [#permalink] 06 Aug 2017, 18:13
Display posts from previous: Sort by

If a, b, and c are positive integers, is (a+b)c divisible by 3? 1) 2-

  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®.