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

Redeem

Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

★★★★★5.0559 reviews
GMATLiveTeach 7 seats left
Chris Peckover
NEXT LIVE COHORT

Oct 13 to Jan 7, 2027

with Chris Peckover

Schedule
Tue, Thu · 8:00 to 10:00 PM ET
Included
40 live hours + 6 months of GMAT OnDemand
  • Live instruction and real-time questions
  • Class recordings and assigned practice
View class & enroll
Limited cohort · enrollment openTarget Test Prep
EALiveTeach 5 seats left
Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

Schedule
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll
Limited cohort · enrollment openTarget Test Prep
GMATOnDemand Start anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 559 reviewsTarget Test Prep

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

Books

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
User avatar
Junior | Next Rank: 30 Posts
Posts: 16
Joined: Fri Jun 25, 2010 6:24 am
Location: Bangalore
Thanked: 1 times

by sgmuthukumar » Thu Sep 23, 2010 7:46 pm
goyalsau wrote:Not able to understand the language
12x-21=(x-1)*8+11

12x-21=8x-8+11

4x=24

x=6

Number of bookshelves =6
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 1179
Joined: Sun Apr 11, 2010 9:07 pmFollowed by: 88 members
Location: Milpitas, CA
Thanked: 447 times

by Rahul@gurome » Thu Sep 23, 2010 8:06 pm
Solution:
Let the number of shelves be n.
Since each shelf contains 12 books, total number of books in all n shelves is 12n.
When 21 books are removed, the remaining number of books is 12n - 21.
Now these 12n - 21 books are rearranged so that (n-1) shelves have 8 books and 1 shelf has 11 books.
So (n-1) shelves now have 8(n-1) books and all n shelves have 8(n-1) + 11 books.
Or 12n - 21 = 8(n-1) + 11.
Or 4n = 24.
Or n = 6.

Or the bookcase has 6 shelves.
Rahul Lakhani
Quant Expert
Gurome, Inc.
https://www.GuroMe.com
On MBA sabbatical (at ISB) for 2011-12 - will stay active as time permits
1-800-566-4043 (USA)
+91-99201 32411 (India)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members
Location: New York, NY
Thanked: 13060 times
GMAT Score:790

by GMATGuruNY » Thu Sep 23, 2010 8:20 pm
goyalsau wrote:Not able to understand the language
Might be easiest just to plug in the answers, which represent the number of shelves.

Answer choice C:
6 shelves, 12 books per shelf, means 6*12 = 72 books.
Removing 21 books leaves 72-21 = 51 books.
8 books on all but 1 shelf = 8*5 = 40 books.
51-40 = 11 books for the last shelf. Success!

The correct answer is C.
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
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 1309
Joined: Wed Mar 17, 2010 11:41 pmFollowed by: 5 members
Thanked: 33 times

by pradeepkaushal9518 » Thu Sep 23, 2010 9:30 pm
great method of solving

actually question is each self can have 12. so suppose there are x selfs then total books will be 12x

but when 21 books are taken out and rearrange then the arranging changed
self contains 8 books and only one contains 11

so 12x-21=(x-1)8+11

solving x=6
A SMALL TOWN GUY
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 866
Joined: Mon Aug 02, 2010 6:46 pm
Location: Gwalior, India
Thanked: 31 times

by goyalsau » Thu Sep 23, 2010 10:30 pm
Thanks for your work Guys,
But i had the problem in understanding the language of the problem it says

So that all shelves but one contained 8 books and the last shelf contained 11 books.

You guys are absolutely right in your approach but can you please explain the above statement.
I know this may be part of CR section but still I would request guys to help me understand the sentence.
Means where to actually separate those two things all but one.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1