A major retail chain in Denmark is studying the shopping habits of couples on the busiest day of the week for consumers visiting its stores. Based on past consumer shopping habits in the records, the retail chain has determined that during busiest day, wives do the shopping 60% of time. When the husband is not shopping, 30% of the time the wife is shopping. Find the probability that:
a. If the wife is shopping, the husband is also shopping.
b. The wife is shopping on the busiest day