SBI PO 21 June 2015 Paper

Total number of balls in the bag
= 5 + 6 + 3 = 14
Total possible outcomes
= selection of 2 balls out of 14 balls
=

14

‌

C2 =

14×13

1×2

= 91
Favourable outcomes = Selection of 2 balls out of 5 red balls+ selection of 2 balls out of 3 green balls
=

5

‌

C2+

3

‌

C2
=

5×4

1×2

+

3×2

1×2

= 10 + 3 = 13
∴ Required probability
=

13

91

=

1

7