NCERT Class XII Mathematics Chapter - - Solutions
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Question : 3
Total: 101
If P(A) = 0.8, P(B) = 0.5 and P(B|A) = 0.4, find
(i) P (A ∩ B)
(ii) P(A | B)
(iii) P(A ∪ B)
(i) P (A ∩ B)
(ii) P(A | B)
(iii) P(A ∪ B)
Solution:
(i) Given P(B|A) = 0.4
⇒
= 0.4
⇒ P ( A ∩ B ) = P ( A ) × 0.4 = 0.8 × 0.4 = 0.32
(ii)P ( A | B ) =
=
= 0.64
(iii)P ( A ∩ B ) = P ( A ) + P ( B ) − P ( A ∩ B ) = 0.8 + 0.5 − 0.32 = 1.3 − 0.32 = 0.98
(ii)
(iii)
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