Element X is a radioactive isotope such that every 28 years, its mass decreases by half. Given that the initial mass of a sample of Element X is 730 grams, write a
function showing the mass of the sample remaining after t years, where the annual
decay rate can be found from a constant in the function. Round all coefficients in the
function to four decimal places. Also, determine the percentage rate of decay per
year, to the nearest hundredth of a percent.