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.

Probability

Problem Solving — algebra and arithmetic (GMAT Focus Edition)
Expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Senior | Next Rank: 100 Posts
Posts: 32
Joined: Thu Feb 24, 2011 1:17 pm
by diegocuenca » Wed Jul 20, 2011 2:07 pm
I'm confused on the difference between these equations

Combined events: E and F = P(E and F) = P(E)P(F)

Conditional probability: the prob. of A and B occurring is the prob. of event A times the prob. of event B, given that A has already occurred.

P(A and B) = P(A) x P(B|A), is | supposed to mean B divided by A to account for A already occurring? If not what does it mean?

What is the difference between both of these equations?

Are
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Quantitative Reasoning |
User avatar
Legendary Member
Posts: 965
Joined: Thu Jan 28, 2010 12:52 amFollowed by: 34 members
Thanked: 156 times
GMAT Score:720

by vineeshp » Thu Jul 21, 2011 6:50 am
hi The | means probability of B given A.

Combined probability is what we apply all the time. Flipping coins twice. Probability of 2 heads is probability of first heads * probability of second heads.

Conditional probability is the case where Probability of the event B occuring is dependent on A occuring. Pulling balls out of a bag, one after the other? If there is a bag of 5 white and 6 red balls. What is the probability of withdrawing 2 whites?

Here the probability of getting white in first is 5/11
But the probability of geting white in second is 4/10. So probability of getting white in the second is dependent on getting a white in the first.
Vineesh,
Just telling you what I know and think. I am not the expert. :)
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Senior | Next Rank: 100 Posts
Posts: 32
Joined: Thu Feb 24, 2011 1:17 pm

by diegocuenca » Tue Jul 26, 2011 10:44 am
Awesome, that was a great explanation.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1