GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 18 Oct 2019, 21:47

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

Doubt on Probability Formula

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Senior Manager
Senior Manager
avatar
G
Joined: 10 Jan 2013
Posts: 297
Location: India
Concentration: General Management, Strategy
GPA: 3.95
GMAT ToolKit User Premium Member Reviews Badge
Doubt on Probability Formula  [#permalink]

Show Tags

New post 07 Apr 2019, 23:54
Hi Everyone,

Could anyone please guide on the usage of the below formula?

\(P(A or B) = P(A) + P(B) - P(A and B)\)

When is the formula applicable? and any particular question in GMAT prep?


Bunuel chetan2u
SVP
SVP
User avatar
V
Status: It's near - I can see.
Joined: 13 Apr 2013
Posts: 1685
Location: India
Concentration: International Business, Operations
Schools: INSEAD Jan '19
GPA: 3.01
WE: Engineering (Real Estate)
Reviews Badge CAT Tests
Doubt on Probability Formula  [#permalink]

Show Tags

New post 08 Apr 2019, 03:08
1
saurabh9gupta wrote:
Hi Everyone,

Could anyone please guide on the usage of the below formula?

\(P(A or B) = P(A) + P(B) - P(A and B)\)

When is the formula applicable? and any particular question in GMAT prep?


Hi Saurabh,

This formula is called "Addition rule for not mutually exclusive events"

For example;

Selecting a perfect cube or an even number.

In this case, there will be n number of perfect cubes that are also even.

If I want to calculate the probability of perfect cubes or even numbers from 1 to 50 inclusive.

Total outcomes = 50.

Required outcomes : Perfect cubes = 1, 8, 27

Even numbers = 2, 4, 6, 8.....50 (Total = 25)

Required probability:

P(A or B) = P(A) + P(B) - P(A & B)

= 3(perfect cubes) + 25(even numbers) - 1(only one number is even & perfect cube = 8)

= 27

So 27/50

Hope this helps
_________________
"Do not watch clock; Do what it does. KEEP GOING."
Intern
Intern
avatar
B
Joined: 21 May 2018
Posts: 14
Re: Doubt on Probability Formula  [#permalink]

Show Tags

New post 11 Apr 2019, 03:34
saurabh9gupta wrote:
Hi Everyone,

Could anyone please guide on the usage of the below formula?

\(P(A or B) = P(A) + P(B) - P(A and B)\)

When is the formula applicable? and any particular question in GMAT prep?


Bunuel chetan2u


Hey!

This formula is pretty much applicable throughout all domains of probability. The important part is getting P(A), P(B), P(A or B) and P(A and B) right.
These can be easily visualised by seeing some Venn Diagrams. If you ever have issues in probability, just draw these diagrams for the events and you will be able to visualise better.

Image
GMAT Club Bot
Re: Doubt on Probability Formula   [#permalink] 11 Apr 2019, 03:34
Display posts from previous: Sort by

Doubt on Probability Formula

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





cron

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne