​Combined, there are 190 ​Asians, Africans,​ Europeans, and Americans in a village. The number of Asians exceeds the number of Africans and Europeans by 60 . The difference between the number of Europeans and Americans is 18 . If the number of Africans is​ doubled, their population exceeds the number of Europeans and Americans by 36 . Determine the number of​ Asians, Africans,​ Europeans, and Americans in this village.

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

Precalculus question, image attached.

Ihonestly have no clue if it's each or none.