The florida tourist commission selected a random sample of 200 people that attended one or more concerts during the first weekend in april of 2010. the survey revealed that 120 concert goers went to orlampa skydome and 100 went to the bithlo megaplax. calculate the probability that a selected concert goer during the same weekend next year will go to either the orlampa skydome or the bithlo megaplax?
book notation: p(a or b) = p(a) + p(b) - p(a and b)

On traditional maps, earth is represented in a flat plane, or by euclidean geometry. however, a globe is a more accurate model that comes from elliptical geometry. how does a globe represent the fact that there are no parallel lines in elliptical geometry? the equator is not parallel to any other latitudinal lines. the north and south poles are never connected by a geodesic. the geodesics connecting the north and south poles never intersect. the geodesics connecting the north and south poles intersect at both of the poles.