A local country club has a membership of 600 and operates facilities that include an 18-hole championship golf course and 12 tennis courts. Before deciding whether to accept new members, the club president would like to know how many members regularly use each facility.
A survey of the membership indicates that 70% regularly use the golf course, 49% regularly use the tennis courts, and 10% use neither of these facilities regularly.
Given that a randomly selected member uses the tennis courts regularly, find the probability that they also use the golf course regularly.