AP EAPCET 23-Aug-2021 Shift 1 Paper

There are two urns
Urn 1 contains 3 green and 2 black balls.
Urn 2 contains 2 green and 5 black balls.
Let A be event of selecting black ball.
Probability of selecting black ball from urn 1 =

2

5

Probability of selecting black ball from urn 2 =

5

7

Since, one urn is selected at random hence
selecting one urn have probability

1

2

,
∴P(A)=

1

2

(

2

5

+

5

7

) =

1

2

(

14+25

35

)=

39

70