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 →

Probability

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 89
Joined: Thu Aug 26, 2010 9:29 am
Thanked: 4 times
by danjuma » Sat Dec 04, 2010 10:13 pm
A basket contains 5 apples of which 1 is spoiled and the rest are good. If Henry is to select 2 apples from the basket simultaneously and at random, what is the probability that 2 apples selected will include the spoiled apple?

a.1/5 b.3/10 c.2/5 d.1/2 e.3/5
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |
Master | Next Rank: 500 Posts
Posts: 437
Joined: Sat Nov 22, 2008 5:06 amFollowed by: 1 member
Location: India
Thanked: 50 times
GMAT Score:580

by beat_gmat_09 » Sat Dec 04, 2010 10:30 pm
Two apples are drawn simultaneously, so order does not matter (both are picked at one time).
There is 1 spoiled apple, 1 good apple, total = 2
Possible outcomes = 5
Probability = 2/5
Hope is the dream of a man awake
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 866
Joined: Mon Aug 02, 2010 6:46 pm
Location: Gwalior, India
Thanked: 31 times

by goyalsau » Sun Dec 05, 2010 1:52 am
beat_gmat_09 wrote:Two apples are drawn simultaneously, so order does not matter (both are picked at one time).
There is 1 spoiled apple, 1 good apple, total = 2
Possible outcomes = 5
Probability = 2/5
it should be 2/5 or 40%
Saurabh Goyal
[email protected]
-------------------------


EveryBody Wants to Win But Nobody wants to prepare for Win.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
GMAT Instructor
Posts: 1031
Joined: Thu Jul 03, 2008 1:23 pmFollowed by: 255 members
Location: Malibu, CA
Thanked: 716 times
GMAT Score:750

by Brian@VeritasPrep » Tue Dec 07, 2010 12:34 pm
Hey guys,

Just one point that may be worth a chime-in on these "simultaneous" probability problems. I think a lot of times the word "simultaneous" throws people off, but when you think about it there's no such thing as perfectly "simultaneous" if you take it all the way down to a nanosecond level, right? At some point your finger touches one apple before the other. So you can solve something like this methodically by using both sequences:

Spoiled, then Not Spoiled (1/5 * 4/4)

Not Spoiled, then Spoiled (4/5 * 1/4)

And then adding them together (4/20 + 4/20 = 8/20 = 2/5)

Or you can think through logically: If he picks 2 and each has a 1/5 chance of being "the spoiled one", then he has two 1/5 chances of a spoiled apple, or a 2/5 total chance.


Just thought it was worth pointing out...the word "simultaneous" in these problems carries a lot more intimidation than it's really worth...
Brian Galvin
GMAT Instructor
Chief Academic Officer
Veritas Prep

Looking for GMAT practice questions? Try out the Veritas Prep Question Bank. Learn More.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1