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

logical gmat maths prob, plz help

Expert replies
by quantskillsgmat » Sat Dec 10, 2011 10:06 pm
three labelled boxes containing red and white balls are mislabeled.it is known that one of the boxes contain only white balls and one only red balls.Third contains mixture of red and white balls.you are required to correctly label the boxes with labels red,white and red and white by picking a sample of one ball from only one box.what is the label on the box you should pick.
a) white
b)red
c)red and white
d)more than one sample is required
Join the discussion
Source: — Problem Solving |

by chufus » Sat Dec 10, 2011 10:38 pm
Quite obviously the answer should be D.
Join the discussion

by Anurag@Gurome » Sat Dec 10, 2011 10:44 pm
If all of the boxes are mislabeled, then the following scenarios are possible...
  • (1) The box labeled with "Red & White" contains either all white or all red balls.
    (2) The box labeled with "Red" contains either all white or mixed balls.
    (3) The box labeled with "White" contains either all red or mixed balls.
Now picking a sample of one ball from the box labeled with "Red and White" will tell us whether the box has all red balls or all white balls.

If the box has all red balls then,
  • From (3) it follows that the box labeled with "White" has mixed balls. Hence, the box labeled with "Red" has all white balls.
If the box has all white balls then,
  • From (2) it follows that the box labeled with "Red" has mixed balls. Hence, the box labeled with "White" has all red balls.
The correct answer is C.

Note : If any two of the three boxes are mislabeled, in that case it is not always possible to correct the labeling by picking one sample.
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/
Join the discussion