My Math Forum  

Go Back   My Math Forum > High School Math Forum > Probability and Statistics

Probability and Statistics Basic Probability and Statistics Math Forum


Reply
 
LinkBack Thread Tools Display Modes
February 3rd, 2014, 09:37 AM   #1
Newbie
 
Joined: Feb 2014

Posts: 3
Thanks: 0

Probability! Help Needed!

I'm taking a probability class and this question was posed by my teacher. it seems simple but me and my friend have been stuck on it for a while. Can anyone help answer this question or at least pose a method to answering it for us?

You are rushing to go away for the weekend and you randomly grab 4 shoes from 4 different pairs in your closet. What is the probability that you have at least one pair?
shcorina is offline  
 
February 3rd, 2014, 10:15 AM   #2
Senior Member
 
tahirimanov's Avatar
 
Joined: Nov 2013
From: Baku

Posts: 502
Thanks: 56

Math Focus: Geometry
Re: Probability! Help Needed!

(1) FIrst fined total chances. C(16,4)
(2) Then calculate One pair and non-pairs C(8,1)*C(14,1)*C(12,1)
(3) Find chances for two pairs C(8,2)

Answer is [(2) + (3)]/(1)
tahirimanov is offline  
February 3rd, 2014, 10:26 AM   #3
Newbie
 
Joined: Feb 2014

Posts: 3
Thanks: 0

Re: Probability! Help Needed!

but the answer has to be less than 1 if its the probability. we know the answer is roughly .77 or exactly 27/35, but we don't know how to get to that.
shcorina is offline  
February 3rd, 2014, 01:46 PM   #4
Global Moderator
 
Joined: May 2007

Posts: 6,680
Thanks: 658

Re: Probability! Help Needed!

Quote:
Originally Posted by shcorina
I'm taking a probability class and this question was posed by my teacher. it seems simple but me and my friend have been stuck on it for a while. Can anyone help answer this question or at least pose a method to answering it for us?

You are rushing to go away for the weekend and you randomly grab 4 shoes from 4 different pairs in your closet. What is the probability that you have at least one pair?
1/7(a) + (6/7)(2/6)(b) + (6/7)(4/6)(3/5)(c) = 27/35
a - prob. that second shoe is match
b - prob. that third shoe is match (second shoe not)
c - prob. that fourth shoe is match (second and third not)

match means match to any previously chosen.
mathman is offline  
February 3rd, 2014, 02:39 PM   #5
Math Team
 
Joined: Dec 2006
From: Lexington, MA

Posts: 3,267
Thanks: 407

Re: Probability! Help Needed!

Hello, shcorina!

Quote:
You randomly grab 4 shoes from 4 different pairs in your closet.
What is the probability that you have at least one pair?












soroban is offline  
February 3rd, 2014, 06:02 PM   #6
Math Team
 
Joined: Oct 2011
From: Ottawa Ontario, Canada

Posts: 13,944
Thanks: 985

Re: Probability! Help Needed!

Quote:
Originally Posted by shcorina
You are rushing to go away for the weekend and you randomly grab 4 shoes from 4 different pairs in your closet.
What is the probability that you have at least one pair?
Corina, what is probability if you grab 5 shoes? Careful....
Denis is offline  
Reply

  My Math Forum > High School Math Forum > Probability and Statistics

Tags
needed, probability



Search tags for this page
Click on a term to search for related topics.
Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Probability Help Needed! shcorina Advanced Statistics 3 May 31st, 2014 07:25 AM
Probability (explanation needed) Nerazzurri_KZ Probability and Statistics 5 April 3rd, 2011 05:36 AM
probability (explanation is needed) safyras Probability and Statistics 1 April 2nd, 2011 08:29 PM
probability (explanation is needed) safyras Probability and Statistics 1 March 31st, 2011 03:23 PM
probability question, help needed! billy Probability and Statistics 1 April 16th, 2010 04:02 PM





Copyright © 2019 My Math Forum. All rights reserved.