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 →

DS: Averages Question

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 68
Joined: Mon May 04, 2009 10:01 pm
by DCJ » Tue Sep 22, 2009 9:39 am
Can someone explain?

Ten different items are for sale in a store, and each is sold at a different price. The average (arithmetic mean) price of these 10 items is $165. If the prices of all the items are changed, will the average price increase?

(1)The five most expensive items each increased in price by 10%
(2) The five least expensive items each decreased in price by 10%

Ans: C
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Data Sufficiency |
Senior | Next Rank: 100 Posts
Posts: 45
Joined: Wed Jun 11, 2008 4:25 pm
Thanked: 4 times
GMAT Score:730

by praky_rules » Wed Sep 23, 2009 4:47 pm
New Average = Old Average + (10% increase in the top 5 priced items + 10% decrease in the bottom 5 priced items)/10.

10% of the top 5 items will be greater than 10% of the bottom 5.

So New Average will be higher than the old average

C.

Two things worth noting are $ 165 is irrelevant and price cannot be negative!(If the numbers were positive and negative, this conclusion is not possible)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1