Question

12) If P(B) =1/3,n(S)=24,then what is n(B)
​

Answer 1

Answer:

Answer

Correct option is

C

42

25

Here, P(A)=

5

2

, P(B)=

10

3

and P(A ∩ B) =

5

1

P(A

′

∣B

′

)=

P(B)

P(A

′

capB

′

)

=

1−P(B)

1−P(A∪B)

=

1−P(B)

1−[P(A)+P(B)−P(A∩B)]

=

1−

10

3

1−(

5

2

+

10

3

−

5

1

)

=

10

7

1−(

10

4+3−2

)

=

10

7

1−

2

1

=

7

5

P(B

′

∣A

′

)=

P(A

′

)

P(B

′

∩A

′

)

=

1−P(A)

1−P(A∪B)

=

1−

5

2

1−

2

1

=

3/5

1/2

=

6

5

[∵P(A∪B)=

2

1

]

∴P(A

′

∣B

′

)⋅P(B

′

∣A

′

)=

7

5

−

6

5

=

42

25