Concentric circles are circles with the same center but different radii. Which equations represent concentric circles along with the circle shown in the graph? Check all that apply. x2 + y2 = 25
(x – 8)² + (y – 9)² = 3
(x – 8)² + (y – 9)² = 14
(x – 8)² + (y + 9)² = 3
(x + 8)² + (y + 9)² = 25
(x + 9)² + (y + 8)² = 3

Suppose that 3% of all athletes are using the endurance-enhancing hormone epo (you should be able to simply compute the percentage of all athletes that are not using epo). for our purposes, a “positive” test result is one that indicates presence of epo in an athlete’s bloodstream. the probability of a positive result, given the presence of epo is .99. the probability of a negative result, when epo is not present, is .90. what is the probability that a randomly selected athlete tests positive for epo? 0.0297