SBI PO 20 June 2015 Paper

Total number of balls in thebag = 4 + 4 + 2 = 10
Total possible outcomes = Selection of 2 balls out of 10 balls
=

10

‌

C2 =

10×9

1×2

= 45
Favourable outcomes = 1 greenball and 1 ball of other colour + 2green balls
=

2

‌

C1×

8

‌

C1+

2

‌

C2
= 2 × 8 + 2 = 18
∴ Required probability
=

18

45

=

2

5