For married couples living in a certain suburb, the probability that the husband will vote on a bond referendum is 0.21, the probability that his wife will vote in the referendum is 0.28, and the probability that both the husband and wife will vote is 0.15. What is the probability that
(a) At least one member of a married couple will vote?
(b) A wife will vote, given that her husband will vote?
(c) A husband will vote, given that his wife does not vote?