• 5 Day FREE Trial
Study Smarter, Not Harder

Available with Beat the GMAT members only code

• Free Practice Test & Review
How would you score if you took the GMAT

Available with Beat the GMAT members only code

• Get 300+ Practice Questions

Available with Beat the GMAT members only code

• Free Trial & Practice Exam
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• Free Veritas GMAT Class
Experience Lesson 1 Live Free

Available with Beat the GMAT members only code

• Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

• 5-Day Free Trial
5-day free, full-access trial TTP Quant

Available with Beat the GMAT members only code

• Award-winning private GMAT tutoring
Register now and save up to \$200

Available with Beat the GMAT members only code

• 1 Hour Free
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

## OG 2016 #87 PS

tagged by: Brent@GMATPrepNow

This topic has 2 expert replies and 1 member reply
Azizakaria Senior | Next Rank: 100 Posts
Joined
29 Sep 2012
Posted:
76 messages
Thanked:
3 times

#### OG 2016 #87 PS

Fri Oct 09, 2015 9:41 am
Elapsed Time: 00:00
• Lap #[LAPCOUNT] ([LAPTIME])
87. The sum of all the integers k such that -26 < k < 24 is
(A) 0
(B) -2
(C) -25
(D) -49
(E) -51

i don't understand why the answer is D

Need free GMAT or MBA advice from an expert? Register for Beat The GMAT now and post your question in these forums!

### GMAT/MBA Expert

Rich.C@EMPOWERgmat.com Elite Legendary Member
Joined
23 Jun 2013
Posted:
8703 messages
Followed by:
460 members
Thanked:
2729 times
GMAT Score:
800
Fri Oct 09, 2015 9:47 am
Hi Azizakaria,

We're limited to the INTEGERS that fall in the range -26 < K < 24....so that would be....

-25, -24, -23.....0.....22, 23

Each of the positive integers form 1 to 23 (inclusive) would be 'cancelled out' by the negative integers from -1 to -23 (inclusive). The sum of ALL of those terms would be 0. But then you have to consider the other remaining integers: -24 and -25. Adding those two numbers gets us -49.

GMAT assassins aren't born, they're made,
Rich

_________________
Contact Rich at Rich.C@empowergmat.com

### GMAT/MBA Expert

Brent@GMATPrepNow GMAT Instructor
Joined
08 Dec 2008
Posted:
10760 messages
Followed by:
1212 members
Thanked:
5144 times
GMAT Score:
770
Fri Oct 09, 2015 9:51 am
Azizakaria wrote:
87. The sum of all the integers k such that -26 < k < 24 is
(A) 0
(B) -2
(C) -25
(D) -49
(E) -51

i don't understand why the answer is D
(-25) + (-24) + (-23) + (-22) + (-21) + . . . . .+ 21 + 22 + 23

Notice that the blue values all cancel out, because for each positive value, there's a negative value with the same magnitude (e.g., -23 + 23 = 0, and -22 + 22 = 0, etc)

So, we're left with (-25) + (-24), which equals -49

_________________
Brent Hanneson – Founder of GMATPrepNow.com
Use our video course along with

Check out the online reviews of our course
Come see all of our free resources

GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMAT’s FREE 60-Day Study Guide and reach your target score in 2 months!
Azizakaria Senior | Next Rank: 100 Posts
Joined
29 Sep 2012
Posted:
76 messages
Thanked:
3 times
Sat Oct 10, 2015 2:44 am
now I understand, thanks for your help, the explanation in the OG is so unclear.

### Best Conversation Starters

1 Vincen 180 topics
2 lheiannie07 65 topics
3 Roland2rule 49 topics
4 ardz24 40 topics
5 LUANDATO 16 topics
See More Top Beat The GMAT Members...

### Most Active Experts

1 Brent@GMATPrepNow

GMAT Prep Now Teacher

146 posts
2 Rich.C@EMPOWERgma...

EMPOWERgmat

103 posts
3 GMATGuruNY

The Princeton Review Teacher

100 posts
4 EconomistGMATTutor

The Economist GMAT Tutor

92 posts
5 Jay@ManhattanReview

Manhattan Review

79 posts
See More Top Beat The GMAT Experts