Question 310151
If P(A)=0.80, P(B)=0.70 AND P(A or B)=0.90, then compute P( A and B). 
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P(A and B) = P(A) + P(B) - P(A or B)
= 0.8+0.7-0.9
= 0.6
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Cheers,
Stan H.
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