Q. 74.0( 5 Votes )

A bag contains 3 white, 4 red and 5 black balls. Two balls are drawn one after the other, without replacement. What is the probability that one is white and the other is black?

Answer :

Given:


Bag contains 3 white, 4 red and 5 black balls.


It is told that two balls are drawn from bag without replacement.


Let us find the Probability of drawing each colour ball from the bag.


P(B1) = P(drawing black ball from bag on first draw)





P(W1) = P(drawing white ball from bag on first draw)





P(B2) = P(drawing black ball from bag on second draw)




P(W2) = P(drawing white ball from bag on second draw)




We need to find:


P(SWB) = P(one ball is White and other is black)


P(SWB) = P(first drawn is White and next is black) + P(first drawn black and next is white)


P(SWB) = P(DWB) + P(DBW)


Since drawing a ball is independent for each bag, the probabilities multiply each other.







The required probability is .


Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
view all courses
RELATED QUESTIONS :