Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
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.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
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 Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart 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 563 reviewsTarget Test Prep

There are 7 red and 5 blue marbles in a jar. In how many way

Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 391
Joined: Sat Mar 02, 2013 5:13 amFollowed by: 4 members
Thanked: 50 times
by rakeshd347 » Sun Sep 29, 2013 7:08 pm
There are 7 red and 5 blue marbles in a jar. In how many ways 8 marbles can be selected from the jar so that at least one red marble and at least one blue marble to remain in the jar?
A. 460
B. 490
C. 493
D. 455
E. 445

OA is D
Last edited by rakeshd347 on Mon Sep 30, 2013 5:18 am, edited 1 time in total.
Top
Join the discussion
Source: — Problem Solving |
User avatar
Legendary Member
Posts: 1555
Joined: Tue Aug 14, 2012 11:18 pmFollowed by: 34 members
Thanked: 448 times
GMAT Score:650

by theCodeToGMAT » Sun Sep 29, 2013 7:55 pm
7R, 5B, --> 8 SELECT

1r3b + 2R2B + 3r1B --> lEFT

=> 7c6 * 5c2 + 7c5 * 5c3 + 7c4 * 5c4

=> 7 * 10 + 21 * 10 + 35 * 5

=> 70 + 210 + 175 = 455

Answer [spoiler]{D}[/spoiler]
R A H U L
Top
Join the discussion
User avatar
Master | Next Rank: 500 Posts
Posts: 283
Joined: Sun Jun 23, 2013 11:56 pmFollowed by: 26 members
Location: Bangalore, India
Thanked: 97 times
GMAT Score:750

by ganeshrkamath » Mon Sep 30, 2013 12:48 am
rakeshd347 wrote:There are 7 red and 5 blue marbles in a jar. In how many ways 8 marbles can be selected from the jar so that at least one red marble and at least one blue marble to remain in the jar?
A. 460
B. 490
C. 493
D. 455
E. 445

OA coming soon.
To select 8 marbles from 7 red and 5 blue:
6R and 2B => 7C6 * 5C2 = 7*10 = 70
5R and 3B => 7C5 * 5C3 = 21*10 = 210
4R and 4B => 7C4 * 5C4 = 35*5 = 175
Total = 70+210+175 = 455

Choose D

Cheers
Every job is a self-portrait of the person who did it. Autograph your work with excellence.

Kelley School of Business (Class of 2016)
GMAT Score: 750 V40 Q51 AWA 5 IR 8
https://www.beatthegmat.com/first-attemp ... tml#688494
Top
Join the discussion
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 » Mon Sep 30, 2013 3:07 am
rakeshd347 wrote:There are 7 red and 5 blue marbles in a jar. In how many ways 8 marbles can be selected from the jar so that at least one red marble and at least one blue marble to remain in the jar?
A. 460
B. 490
C. 493
D. 455
E. 445
Good ways = Total ways - Bad ways.

Total ways:
Number of ways to select 8 marbles from 12 options = (12C8) = (12*11*10*9*8*7*6*5)/(8*7*6*5*4*3*2*1) = 495.

Bad way 1: No RED marbles left in the jar
For none of the 7 red marbles to be left in the jar, exactly 1 of the 5 blue marbles must be selected.
Number of ways to choose 1 blue marble from 5 options = 5C1 = 5.

Bad way 2: No BLUE marbles left in the jar
For none of the 5 blue marbles to be left in the jar, exactly 3 of the 7 red marbles must be selected.
Number of ways to choose 3 red marbles from 7 options = 7C3 = (7*6*5)/(3*2*1) = 35.

Good ways:
Total ways - bad ways = 495 - 5 - 35 = 455.

The correct answer is D.
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