Question 1154182
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When the information is given in this form, use the definition of conditional probability directly.<br>
P(A|B) is the probability that A (also) occurs, given that B occurs.  So the numerator of the probability fraction is the probability that both A and B occur, and the denominator is the probability that B occurs.<br><pre>
            P(AnB)
  P(A|B) = --------
             P(B)</pre>
For this problem...<br>
a. P(A|B) = 0.1/0.2 = 0.5
b. P(B|A) = 0.1/0.4 = 0.25<br>