This exercise uses the radioactive decay model. The half-life of radium-226 is 1600 years. Suppose we have a 23-mg sample. (a) Find a function m(t) mo2 t/h that models the mass remaining after t years. m(t) 23 2 - 1600 (b) Find a function m(t) moet that models the mass remaining after t years. (Round your r value to six decimal places.) m(t)= X (c) How much of the sample will remain after 2000 years? (Round your answer to one decimal place.) mg (d) After how many years will only 19 mg of the sample remain? (Round your answer to one decimal place.) vr