NCERT Class XII Mathematics Chapter - - Solutions

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Question : 22
Total: 101
A die marked 1, 2, 3 in red and 4, 5, 6 in green is tossed. Let A be the event, ‘the number is even’ and B be the event, ‘the number is red’. Are A and B independent ?
Solution:  
The sample space is S = {1, 2, 3, 4, 5, 6}.
Given that A : ‘number is even’ ⇒ A = {2, 4, 6} and B : ‘number is red’
⇒ B = {1, 2, 3} ⇒ A ∩ B = {2}.
Now, P(A)=
3
6
=
1
2
, P(B)=
3
6
=
1
2
and P(AB)=
1
6

P(AB)P(A)P(B) (
1
6
1
2
.
1
2
)

⇒ A and B are not independent.
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