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P(A) = 0.60 , P( AUB ) = 0.85 and P( A∩B ) = 0.05.

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Apply formula : P( AUB ) = P(A) + P(B) − P( A∩B )
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Substitute : P(A) = 0.6 , P( A∩B ) = 0.05 and P( AUB ) = 0.85.
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0.85 = 0.6 + P(B) − 0.05.
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0.85 = 0.55 + P(B)
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P(B) = 0.85− 0.55.
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P(B) = 0.3
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P(B) = 0.3.
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