9. After a mild heart attack, Mary spent 3 days in a coronary care unit. Her room bill was 2,898. What was her daily room rate ?

Solve: 3x+y=6 4x-2y=18 show all work !

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

With finding limits of multi variable !