Expert: Paul Klarreich - 1/31/2011

Question
An investor holds shares in three independent companies:  
Company A, Company B, Company C. An analyst predicts the probability of profit increases for each company as follows:
Company A: 0.70
Company B: 0.50
Company C: 0.65
--If the analyst's predictions are true,what is the probability that atleast one company shows a profit increase? Express your answer to the nearest hundredth of a percent.

Answer
Questioner: Andrea
Country: Canada
Category: Advanced Math
Private: No
Subject: Probability
Question: An investor holds shares in three independent companies:  
Company A, Company B, Company C. An analyst predicts the probability of profit increases for each company as follows:
Company A: 0.70
Company B: 0.50
Company C: 0.65
--If the analyst's predictions are true,what is the probability that atleast one company shows a profit increase? Express your answer to the nearest hundredth of a percent.
.............................................
Basic method for these:

p(at least one of A,B,C,...) = 1 - p(none of A,B,C,...)

and

p(none of A,B,C,...) = p(not A) * p(not B) * p(not C) ...

That should do it.