Ineed with these because recently we have been learning this and i don't get any of this.

Barbara deposited $300 in the bank. if the bank pays her simple interest at the rate of 4 percent per year, how much money will she have in her account at the end of 9 months?

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

Which of the following can be used to explain a statement in a geometric proof?