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 →

median/average question

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 53
Joined: Thu Apr 12, 2007 12:32 am
Thanked: 1 times
by jc114 » Wed Aug 20, 2008 9:57 pm
Set M has 15 numbers while Set K has 17 numbers. If one number from set K is taken and moved into set M, is the average of K larger than M?
(1) after moving a number into M, the median of M is smaller than the median of K.
(2) after moving a number into M, the average of M and the average of K both increased.

OA is B

Is there a better way to solve this than plugging #s??
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Data Sufficiency |
Legendary Member
Posts: 661
Joined: Tue Jul 08, 2008 12:58 pm
Location: France
Thanked: 48 times

by pepeprepa » Thu Aug 21, 2008 1:24 am
Why do you want to do something else than plugging?
I find it efficient here, you solve the question in a very few time.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 58
Joined: Fri Apr 04, 2008 12:36 pm
Thanked: 4 times
GMAT Score:680

Re: median/average question

by mim3 » Thu Aug 21, 2008 8:47 am
jc114 wrote:Set M has 15 numbers while Set K has 17 numbers. If one number from set K is taken and moved into set M, is the average of K larger than M?
(1) after moving a number into M, the median of M is smaller than the median of K.
(2) after moving a number into M, the average of M and the average of K both increased.

OA is B

Is there a better way to solve this than plugging #s??
You can plug in #'s but for me that would be really time consuming and I'd probably make a mistake along the way. Just by understanding how mean and median relate to each other, you can solve the problem without any calculation.

1. So we move a number from K to M and M's median is smaller than K's. I don't think this tells us much other than exactly what's stated. We don't know if K's was smaller before... we definitely don't know anything about the average. Insufficient

2. We move a number from K into M and both averages increase. From this we know that this number was below K's mean and above M's mean. So, K's mean is larger than M's. Sufficient.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 53
Joined: Thu Apr 12, 2007 12:32 am
Thanked: 1 times

by jc114 » Thu Aug 21, 2008 4:37 pm
I guess but who wants to plug in 15 and 17 #s?
I just want to understand the theory behind medians and averages..
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1