If i buy something for $25.40 with 15% tax, what would it be?

What does it mean by solve the exponential equation for x?

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

Amachine part consists of a half sphere and a cylinder, as shown in the figure. the total volume of the part is π cubic inches.