We are studying the success rate of newly opened hotel-casinos in Las Vegas. We measure that (a) 65% of these hotel-casinos generate positive revenue from the gambling business (i. e. the casino), and (b) 45% generate positive revenue from the hospitality business (i. e. the hotel). We are also told that 20% of these hotel-casinos are profitable in both gambling and hospitality. a. What percentage of the newly opened hotel casinos generate positive revenue either from gambling or from hospitality?
b. What percentage of the newly opened hotel casinos generate positive revenue neither from gambling nor from hospitality?