Which system of equations has a solution of approximately (–0.4, 1.1)?
x + 3 y = 3 and 2 x minus y = negative 2
x minus 3 y = negative 3 and 2 x + y = 2
x minus 3 y = negative 3 and 2 x minus y = negative 2
x + 3 y = 3 and 2 x + y =2

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