My Math Forum  

Go Back   My Math Forum > College Math Forum > Advanced Statistics

Advanced Statistics Advanced Probability and Statistics Math Forum

LinkBack Thread Tools Display Modes
November 6th, 2017, 08:43 AM   #1
Joined: Nov 2017
From: San Diego, CA

Posts: 1
Thanks: 0

Probability problem

I need help with my homework problem:

Suppose there are two closed boxes. In each box are two coins; one box contains two gold coins, the other contains one gold coin and one silver coin. A coin will be drawn from one of these two boxes. Assume that each box has an equal chance of being chosen, and that within each box, each coin has an equal chance of being chosen. When the coin is drawn, it turns out to be gold. What is the probability that the other coin in the same box is gold?
VarunSoon is offline  
November 6th, 2017, 09:37 AM   #2
Senior Member
romsek's Avatar
Joined: Sep 2015
From: Southern California, USA

Posts: 1,602
Thanks: 816

There are two boxes, label the one w/2 gold coins $GG$ and the one with one gold, one silver coin $GS$

$P[G|G] = P[G|G \wedge GS]P[GS] + P[G|G \wedge GG]P[GG] = (0)(1/2) + (1)(1/2) = 1/2$
romsek is offline  
November 6th, 2017, 01:47 PM   #3
Global Moderator
Joined: May 2007

Posts: 6,378
Thanks: 542

Number the coins 1-4, where 1 and 2 are gold in box 1, while 3 is gold in box 2 and 4 is silver in box 2.
choose 1 other is gold
choose 2 other is gold
choose 3 other is silver
choose 4 - not gold

Net result - probability other coin is gold is 2/3.
mathman is offline  

  My Math Forum > College Math Forum > Advanced Statistics

probability, problem

Thread Tools
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
Probability Problem / Insurance problem bsjmath Advanced Statistics 2 March 1st, 2014 03:50 PM
Probability Problem swickedman Advanced Statistics 2 March 29th, 2013 01:51 PM
Problem on probability soniclavier Advanced Statistics 8 June 13th, 2012 04:51 AM
Probability problem lynn0218 Probability and Statistics 2 February 14th, 2010 12:55 AM
A Probability Problem Djelorean Algebra 3 September 17th, 2007 04:09 PM

Copyright © 2017 My Math Forum. All rights reserved.