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

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

Sequence

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 304
Joined: Wed Jan 27, 2010 8:35 amFollowed by: 3 members
Location: International Space Station
Thanked: 11 times
by Aman verma » Thu Aug 11, 2011 9:38 am
Q: In a sequence which is in descending order, sum of all its terms , except for the first term , is equal to -36, the sum of all its terms,except for the last term, is zero, and the difference of the tenth and the sixth term is equal to -16, then what will be the first term of this sequence.

a)16

b)20

c)-16

d)-20

e)24
800. Arjun's-Bird-Eye
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pmFollowed by: 523 members
Location: Milpitas, CA
Thanked: 1854 times
GMAT Score:770

by Anurag@Gurome » Thu Aug 11, 2011 10:07 am
Unless the type of the sequence is mentioned the first term cannot be determined uniquely. Please check the question again. I believe there it is mentioned as an arithmetic progression.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 2789
Joined: Tue Jul 26, 2011 12:19 amFollowed by: 43 members
Location: Chennai, India
Thanked: 206 times
GMAT Score:640

by GmatKiss » Thu Aug 11, 2011 11:45 am
I agree with Anurag, some data is missed out!
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 304
Joined: Wed Jan 27, 2010 8:35 amFollowed by: 3 members
Location: International Space Station
Thanked: 11 times

by Aman verma » Thu Aug 11, 2011 11:58 am
Yep ! it is an Arithmetic Progression. Regret the shortfall in information.
800. Arjun's-Bird-Eye
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pmFollowed by: 523 members
Location: Milpitas, CA
Thanked: 1854 times
GMAT Score:770

by Anurag@Gurome » Thu Aug 11, 2011 12:08 pm
Aman verma wrote:Q: In a sequence which is an arithmetic progression in descending order, sum of all its terms , except for the first term , is equal to -36, the sum of all its terms,except for the last term, is zero, and the difference of the tenth and the sixth term is equal to -16, then what will be the first term of this sequence
Say, the first term is a and the common difference is d and there are n terms in total.
Hence, tenth term = (a + 9d) and sixth term = (1 + 5d)
Therefore, (a + 9d) - (a + 5d) = -16 ---> d = -4

Last term, i.e. n-th term = a + (n - 1)d

Now, first term - last term = 36
---> a - a + (n - 1)d = 36
---> -(n - 1)d = 36
---> n = 10

Now sum of first 9 terms is equal to zero. As these 9 terms are uniformly spaced, their average must be equal to their median, i.e. the 5th term will be equal to zero. Hence, (a + 4d) = 0 ---> a = -4d = 16

The correct answer is A.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 2789
Joined: Tue Jul 26, 2011 12:19 amFollowed by: 43 members
Location: Chennai, India
Thanked: 206 times
GMAT Score:640

by GmatKiss » Thu Aug 11, 2011 12:35 pm
IMO:A

10x-6x= -16 x=-4

sum except for the first term is -36 => last term must be -36 or -16(last but one),-20
sum except last element is 0 => first term should be 36 or 16,20(second)

with 36 not in the option, you go for 16!
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 51
Joined: Wed Aug 03, 2011 4:51 pm
Thanked: 2 times

by pinchharmonic » Thu Aug 11, 2011 4:44 pm
GmatKiss wrote:IMO:A

10x-6x= -16 x=-4

sum except for the first term is -36 => last term must be -36 or -16(last but one),-20
sum except last element is 0 => first term should be 36 or 16,20(second)

with 36 not in the option, you go for 16!
you think you can elaborate on that a bit?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 304
Joined: Wed Jan 27, 2010 8:35 amFollowed by: 3 members
Location: International Space Station
Thanked: 11 times

by Aman verma » Fri Aug 12, 2011 5:57 am
OA[spoiler]a)[/spoiler]
800. Arjun's-Bird-Eye
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1