A room has to be painted and worker A does 1/3 of the work then leaves. Next worker B does 1/4 of the remaining work and then leaves and finally worker C does 1/5 of the remaining work and then leaves. What fraction of the room still needs to be painted?
a)3/5
b)2/5
c)13/60
d)7/15

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