Element X is a radioactive isotope such that every 20 years, its mass decreases by half. Given that the initial mass of a sample of Element X is 410
grams, how long would it be until the mass of the sample reached 270 grams,
to the nearest tenth of a year?

The tuition costs, c, for a local community college are modeled by c(h) = 250 + 200h, where h represents the number of credit hours taken. the local state university has tuition costs, s, modeled by the function s(h) = 300 + 180h. how many credit hours will a student have to take for the two tuition costs to be equal? round the answer to the nearest tenth of an hour.