Question

if a bag contains 3 red 5 black and 6 green balls and we draw 4 balls from bag then find the probability that 2 of them are green?

Answer 1

There are two bags say A and B.
Bag A consists of 5 red and 3 green balls.
Bag B consist of 4 red and 6 green balls.
One ball is drawn from each bag.
There are two possibilities:
(1)Red ball from bag A and green ball from bag B.
(2)Green ball from bag B and red ball from bag B.
Hence required probability is
=(5/8)*(6/10)+(3/8)*(4/10)
=21/40