The sum of 3 consecutive numbers is definitely:
A. Positive.
B. Divisible by 2.
C. Divisible by 3.
D. Divisible by 4.
E. Divisible by 5.
[spoiler]OA=C[/spoiler].
I know that the sum will be an odd number, therefore it won't be divisible by 2. But, how can I know that it is divisible by 3? I'd appreciate some help here.
The sum of 3 consecutive numbers is definitely:
This topic has expert replies
-
- Legendary Member
- Posts: 1622
- Joined: Thu Mar 01, 2018 7:22 am
- Followed by:2 members
- GMATGuruNY
- GMAT Instructor
- Posts: 15539
- Joined: Tue May 25, 2010 12:04 pm
- Location: New York, NY
- Thanked: 13060 times
- Followed by:1906 members
- GMAT Score:790
Try to show that four of the five answer choices are WRONG.Gmat_mission wrote:The sum of 3 consecutive numbers is definitely:
A. Positive.
B. Divisible by 2.
C. Divisible by 3.
D. Divisible by 4.
E. Divisible by 5.
Case 1: -2, -1, 0
Sum = -2 + (-1) + 0 = -3.
The resulting sum is not positive, nor is it divisible by 2, 4 or 5.
Eliminate A, B, D and E.
The correct answer is C.
The sum of 3 consecutive integers can be represented and then simplified as follows:
x + (x+1) + (x+2) = (x+x+x) + (1+2) = 3x + 3 = (3)(x+1) = (3)(integer) = multiple of 3.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
GMAT/MBA Expert
- Jeff@TargetTestPrep
- GMAT Instructor
- Posts: 1462
- Joined: Thu Apr 09, 2015 9:34 am
- Location: New York, NY
- Thanked: 39 times
- Followed by:22 members
Lets sum a few consecutive numbers:Gmat_mission wrote:The sum of 3 consecutive numbers is definitely:
A. Positive.
B. Divisible by 2.
C. Divisible by 3.
D. Divisible by 4.
E. Divisible by 5.
1 + 2 + 3 = 6
10 + 11 + 12 = 33
We see that the sum of 3 consecutive integers will always be divisible by 3.
Answer: C
Jeffrey Miller
Head of GMAT Instruction
[email protected]
See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews
GMAT/MBA Expert
- Brent@GMATPrepNow
- GMAT Instructor
- Posts: 16207
- Joined: Mon Dec 08, 2008 6:26 pm
- Location: Vancouver, BC
- Thanked: 5254 times
- Followed by:1268 members
- GMAT Score:770
Another approach:Gmat_mission wrote:The sum of 3 consecutive numbers is definitely:
A. Positive.
B. Divisible by 2.
C. Divisible by 3.
D. Divisible by 4.
E. Divisible by 5.
Let x = the smallest integer
So, x+1 = the next integer
And x+2 = the last integer
Sum of 3 consecutive numbers = x + (x+1) + (x+2)
= 3x + 3
= 3(x+1)
As we can see, the sum MUST be a multiple of 3
Or we can say the sum MUST be a divisible by 3
Answer: C
Cheers,
Brent
GMAT/MBA Expert
- Scott@TargetTestPrep
- GMAT Instructor
- Posts: 7247
- Joined: Sat Apr 25, 2015 10:56 am
- Location: Los Angeles, CA
- Thanked: 43 times
- Followed by:29 members
We can let n = 1st number, so n + 1 and n + 2 will be the 2nd and 3rd numbers, respectively. We see that n + n + 1 + n + 2 = 3n + 3, which is definitely divisible by 3.Gmat_mission wrote:The sum of 3 consecutive numbers is definitely:
A. Positive.
B. Divisible by 2.
C. Divisible by 3.
D. Divisible by 4.
E. Divisible by 5.
[spoiler]OA=C[/spoiler].
Answer: C
Scott Woodbury-Stewart
Founder and CEO
[email protected]
See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews