The radioactive decay of radon-222 can be modeled by the function A = Ce-0. 18131, where A is the amount remaining, C is the original amount, and t is the time in days. If there are 15 mg of randon-222 sealed in a glass tube, how much will remain in the tube after 8 days? 0.53 mg 3.52 mg 187.69 mg 4.26 mg