a survey of a group of 116 tourists was taken in st. louis. the survey showed the following: 66 of the tourists plan to visit gateway arch; 50 plan to visit the zoo; 10 plan to visit the art museum and the zoo, but not the gateway arch; 14 plan to visit the art museum and the gateway arch, but not the zoo; 18 plan to visit the gateway arch and the zoo, but not the art museum; 9 plan to visit the art museum, the zoo, and the gateway arch; 14 plan to visit none of the three places. how many plan to visit the art museum only?
