Ms Hogan has more than 20 students in her class. when she divides the class into groups of 5, there are 4 students left over.
when she divides the class into groups of 4, there is 1 student left over.
what is the least number of students that could be in ms Hogan's class?

i need that asap pleasee

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