Consider the probability model with sample space (A,B,C} and P(A)=0.1, P(B)=0.1, P(C)=0.8.Then
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The sum of all the possible events is 1, which means that all the events are independent of the others, in that case
P(A or C) = P(A)+P(C) = 0.1 + 0.8 = 0.9
P(B and C) = P(B)*P(C) = 0.1 * 0.8 = 0.08