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 →

The 22nd Term

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
User avatar
Site Admin
Posts: 2567
Joined: Thu Jan 01, 2009 10:05 amFollowed by: 550 members
Thanked: 712 times
GMAT Score:770

by DanaJ » Tue Apr 14, 2009 3:40 pm
There's trusty formulas for this one.

I. 1 + 2 + 3 + ... + n = n(n+1)/2

II. 1^2 + 2^2 + 3^2 + ... + n^2 = n(n+1)(2n+1)/6.

Now apply that to n = 22:

A will be 22*23/2 = 11*23

The other number you're looking for will be 22*23*45/6 = 11*23*45/3 = 11*23*15 = 15 A.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
MBA Student
Posts: 1194
Joined: Sat Aug 16, 2008 9:42 pmFollowed by: 17 members
Location: Paris, France
Thanked: 71 times
GMAT Score:710

by gmat740 » Tue Apr 14, 2009 7:07 pm
I. 1 + 2 + 3 + ... + n = n(n+1)/2

II. 1^2 + 2^2 + 3^2 + ... + n^2 = n(n+1)(2n+1)/6.
I would like to proceed from where DanaJ left

II. [n(n+1)/2 ]*[(2n+1)/3]

= A*[(2n+1)/3]

put n= 22

A*[45/3]

=A*15 or 15A

Hope this helps

Karan
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 487
Joined: Fri Mar 27, 2009 5:49 am
Thanked: 36 times

by dtweah » Tue Apr 14, 2009 7:52 pm
gmat740 wrote:
I. 1 + 2 + 3 + ... + n = n(n+1)/2

II. 1^2 + 2^2 + 3^2 + ... + n^2 = n(n+1)(2n+1)/6.
I would like to proceed from where DanaJ left

II. [n(n+1)/2 ]*[(2n+1)/3]

= A*[(2n+1)/3]

put n= 22

A*[45/3]

=A*15 or 15A

Hope this helps

Karan
Voila!! Question designed to explore the link between the two formulas.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pmFollowed by: 11 members
Thanked: 331 times

by cramya » Tue Apr 14, 2009 8:03 pm
i would go with D

a^2

each term is squared

first series 22nd term A

second series 22nd term A^2
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Master | Next Rank: 500 Posts
Posts: 435
Joined: Sat Sep 27, 2008 2:02 pmFollowed by: 1 member
Location: San Jose, CA
Thanked: 43 times
GMAT Score:720

by dumb.doofus » Tue Apr 14, 2009 9:47 pm
Yes.. the question just asks for the 22nd term.. which if it is A in the first sequence , then it would be A^2 in the second sequence..
answer seems to be D. or am I missing something..
One love, one blood, one life. You got to do what you should.
https://dreambigdreamhigh.blocked/
https://gmattoughies.blocked/
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 151
Joined: Wed Feb 11, 2009 2:45 am
Thanked: 3 times

by deepoe » Thu Apr 16, 2009 2:30 am
Can't u use the formula A + (n-1)D ?
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 221
Joined: Wed Jan 21, 2009 10:33 amFollowed by: 1 member
Thanked: 12 times

by krisraam » Thu Apr 16, 2009 6:51 pm
deepoe wrote:Can't u use the formula A + (n-1)D ?
You can use that formula only if its a arithmetic progresssion.

Thanks
Raama
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1