Question

A bag contains 6 white balls and 4 black balls.A ball is drawn and is put back in the bag with 5 balls of the same colour as that of the ball drawn.A ball is drawn again at random.What is the probability that the ball drawn now is white

Answer 1

Answer:

We have a total of 15 balls,

6 red

5 white

4 black

No. Of non-red balls= 5+4= 9

Now, let X be the 1st non-red balls

P(X)=9÷15

=3/5

Again, let Y be the 2nd non-red ball

Since one selection is already made there are 14 balls remaining out of which 8 are non-red

So, P(Y)=8÷14

=4/7

Then, total probability of not getting a red ball

=P(X)×P(Y)

=3/5×4/7

= 12/35