Posted by Emily on Tuesday, December 7, 2010 at 5:11pm.
An Urn contains 7 red and 3 white balls. Two balls are drawn in succession without replacement. If the second ball is white, what is the probability that the first ball was white?

statistics  PsyDAG, Tuesday, December 7, 2010 at 11:37pm
It doesn't matter what the second ball is. Since no balls have been drawn before the first ball, probability = 3/10.

statistics  lanya, Wednesday, July 1, 2015 at 10:47am
A box contain 3 red balls and 6 white balls. One ball was pulled and was seen its collar, and after that was pulled another ball.Find the probability that the first ball was white and the second was red ?
Answer This Question
Related Questions
 statistics  An urn contains white and red balls. Four balls are randomly drawn ...
 statistics  An urn contains white and red balls. Four balls are randomly drawn ...
 MATH(STATISTICS)  Urn A contains R red balls and W white balls, urn B contains ...
 MATH  Urn A contains six white balls and three black balls. Urn B contains ...
 mathematical statistic  Urn A contains six white balls and three black balls. ...
 Math  A bag contains 5 red balls, 4 white balls, and 3 black balls. Two balls ...
 Probability  A box contains 10 balls. Three of them are white, five are red, ...
 statistics  An urn contains 10 balls of which 6 are white, 3 are red and 1 is ...
 statistics  An urn contains 10 balls of which 6 are white, 3 are red and 1 is ...
 MATH  An urn contains 5 white and 6 black balls. Four balls are randomly drawn ...
More Related Questions