Confused on how i would use conditional probability for this question?

6. After a recent Canadian census it was discovered that among all of the families in Canada, 40% have no children, 25% have 1 child, 18% have 2 children, 10% have 3 children, 5% have 4 children, and 2% have 5 or more children. If a Canadian family is selected at random, determine the probability that the family: a) has more than 2 children; b) has more than 2 children given that it has at least 1 child