Don't Know how to work out this question:
An advertising executive studied TV viewing habits of married men and women during prime time hours. He determined that during prime time, husbands watch TV 60% of the time. When the husband is watching TV, 40% of the time the wife is also watching. When the husband is not watching, 30% of the time the wife is.
a.) Find the probability that if the wife is watching TV then the husband is also.