In a certain city, three newspapers A, B. and C are published. Suppose that 60 percent of the families in the city subscribe to newspaper A, that 40 percent of the families subscribe to newspaper B, and that 30 percent subscribe to newspaper C. Suppose also that 20 percent of the families subscribe to both A and B, that 10 percent subscribe to both A and C, that 20 percent subscribe to both B and C, and that 5 percent subscribe to all three newspapers A, B, and C. What percentage of the families in the city subscribe to at least one of the three newspapers?