BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

integers

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 129
Joined: Mon Dec 15, 2008 11:43 pm
Location: Hyderabad
Thanked: 2 times

integers

by naaga » Sat Feb 14, 2009 12:59 pm
If a, b, and c are integers, is the number 3(a+b)-c divisible by 3?
(1) a + b is divisible by 3.
(2) c is divisible by 3.


folks exp plz....
Top
Source: — Data Sufficiency |
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Sat Feb 14, 2009 1:04 pm
I would go with B

Question : Is 3 (a+b) - c divisible by 3

3(a+b) is always divisible by 3 so the real question is Is c divisible by 3. If it is then the expression 3(a+b) -c is divisible by 3

Stmt I

a+b divisible by 3

No idea about c therefore the expression 3 (a+b) - c may or may not be divisible by 3

INSUFF

Stm II
c is divisible by 3
Exactly what we need

SUFF
Last edited by cramya on Sat Feb 14, 2009 1:10 pm, edited 1 time in total.
Top
User avatar
Master | Next Rank: 500 Posts
Posts: 226
Joined: Tue Jan 13, 2009 1:27 pm
Thanked: 23 times
Followed by:1 members

Re: integers

by awesomeusername » Sat Feb 14, 2009 1:07 pm
naaga wrote:If a, b, and c are integers, is the number 3(a+b)-c divisible by 3?
(1) a + b is divisible by 3.
(2) c is divisible by 3.


folks exp plz....
I would say B.

(1) If a+b is divisible by 3, (say a+b = 3) and c=1, then 3(3) -1 = 8, which is not divisible by 3.

(2) If c is divisible by 3, then we have a multiple of 3 - 3, which is still a multiple of 3. For instance, 3(5) - 3 = 3(5-1) = 12.
Top
Post new topic Post Reply
• Page 1 of 1