P(s) = 45/125 = 0.360 P(A&C) = 38/125 = 0.304 Probability that one is not in Arts and Crafts = 1- P(A&C) = 1-0.304 = 0.696
Therefore, Probability that the child selected is in swimming when its known they didn't sign for Arts and craft = Probability they signed for swimming * Probability that they didn't sign for Arts and Crafts = 0.360*0.696 = 0.25056