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 →

sets

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 117
Joined: Mon Oct 27, 2008 5:08 pm
Thanked: 1 times
by [email protected] » Mon Mar 02, 2009 12:07 pm
400 people join the local gym. 60 people take aerobics, 60 people take yoga. Of these, 30 people take both aerobics and yoga. if a customer is chosen at random from the gym, what is the probability that customer takes aerobics or yoga but not both?


[spoiler]3/20[/spoiler]
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
Master | Next Rank: 500 Posts
Posts: 160
Joined: Fri May 30, 2008 7:10 pm
Thanked: 10 times
GMAT Score:600

by dendude » Mon Mar 02, 2009 2:28 pm
60 take yoga and 60 take aerobics.
And 30 take both, meaning 30 take yoga only, 30 take aerobics only and 30 take both.

The required probability would be, 30/400 + 30/400
= (2*30)/400
= 3/20
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 33
Joined: Thu Feb 19, 2009 7:19 pm
Location: DC
Thanked: 2 times

Re: sets

by iwant700plus » Mon Mar 02, 2009 2:46 pm
The best way is to draw two sets that intersect (see my attachment). It's easy to visualize that what you are looking for is the area outside of the intersection which is given by

30/400+30/400=3/20

[email protected] wrote:400 people join the local gym. 60 people take aerobics, 60 people take yoga. Of these, 30 people take both aerobics and yoga. if a customer is chosen at random from the gym, what is the probability that customer takes aerobics or yoga but not both?


[spoiler]3/20[/spoiler]
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1