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 Starts Oct 17
Chris Peckover, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Chris Peckover, 100th-Percentile GMAT Scorer

Oct 17 · Chris Peckover
Sat · 11:00 AM to 2:00 PM ET
Oct 20 · Chris Peckover
Tue, Thu · 8:00 to 10:00 PM ET
Oct 25 · Josh Braslow
Sun · 1:00 to 4:00 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
EALiveTeachOnDemand 5 seats left Start anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

165+ EA score guarantee
$05-day trial no automatic billing
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 Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget 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.

When 2 numbers are removed from 1, 3, 5, 7, 9, 11, 13, 15, 1

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Elite Legendary Member
Posts: 3991
Joined: Fri Jul 24, 2015 2:28 amFollowed by: 37 members
Location: Las Vegas, USA
Thanked: 19 times
by Max@Math Revolution » Wed Mar 02, 2016 9:54 pm
When 2 numbers are removed from 1, 3, 5, 7, 9, 11, 13, 15, 17, and 19, is the median of new 8 numbers equal to the average (arithmetic mean) of new 8 numbers?

1) The median of new 8 numbers is 10
2) The average (arithmetic mean) of new 8 numbers is 10


* A solution will be posted in two days.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
Junior | Next Rank: 30 Posts
Posts: 11
Joined: Thu Mar 03, 2016 1:34 am
Thanked: 1 times

by Dario@VinciaPrep » Thu Mar 03, 2016 2:57 am
This is a set of 10 consecutive odd numbers.
We know that for this set, the average is 10 and the median is 10.
You can see it as two small sets of 5 consecutive integers:
1, 3, 5, 7, 9 and 11, 13, 15, 17, and 19

Statement 1 alone states that the median of the new 8-numbers set is 10. It means that you have to take out one number for each subset, which means that the median will be 10 as in the original set.
Think about this example...
If you remove 1 and 19, the average will still be 10.
If you remove 1 and another number from the second subset, the average will not be 10.
This means that STATEMENT 1 ALONE IS NOT SUFFICIENT.

Statement 2 alone states that the average of the new 8-numbers set is 10. It means that you have to take out two numbers, and that the sum of the two numbers needs to be 20.
You can take out:
- 1 and 19
- 3 and 17
- 5 and 15
- 7 and 13
- 9 and 11
In each of this couples, one element is taken from the first subset, and the other is taken from the second subset. This means that the new median will still be 10, as in the original set - the same value of the new average.
This means that STATEMENT 2 ALONE IS SUFFICIENT.

The answer is (B).
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Elite Legendary Member
Posts: 3991
Joined: Fri Jul 24, 2015 2:28 amFollowed by: 37 members
Location: Las Vegas, USA
Thanked: 19 times

by Max@Math Revolution » Sun Mar 06, 2016 2:31 am
Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

When 2 numbers are removed from 1, 3, 5, 7, 9, 11, 13, 15, 17, and 19, is the median of new 8 numbers equal to the average (arithmetic mean) of new 8 numbers?

1) The median of new 8 numbers is 10
2) The average (arithmetic mean) of new 8 numbers is 10


Modify the original condition and the question. In order to make mean=median happen, there should be one pair amongst numbers (1,19),(3,17),(5,15),(7,13),(9,11) which should be removed. For 2), it is always yes and sufficient. On the other hand, for 1), if (1,19) is removed, it is yes, but if (1,17) is removed, it is no. Therefore, the answer is B.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1