UPSC NDA Math Model Paper 8

In the given case
Case A: Selecting the bag and there are 2 bags having an equal possibility of getting choose
∴P(A)=

1

2

Case B: Selection of the green shirt from any bag
∴P(B)=

4

10

+

2

5

=

4

5

Now P(A∩B)=P(A)×P(B)
⇒P(A∩B)=

1

2

×

4

5

=

2

5

Probability of case A happens given that case B definitely has happened
P(A|B)=

P(A∩B)

P(B)

⇒P(A|B)=

2 5

4 5

=

1

2