A chemist has a 100-gram sample of O c. 100 a radioactive material. He records the amount of radioactive material every week for 6 weeks and obtains the following data. Complete parts (a) (f). 30 Weight, y Week, x (in grams) (d) From the result found in part (b), determine the half-life of the radioactive material. 0 100.0 87.1 The half-life of the material is about weeks . ..... 2 73.8 (Round to one decimal place as needed.) W 66.4 55.8 (e) How much radioactive material will be left after 50 weeks? 48.2 41.7 After 50 weeks, about gram(s) of radioactive material will be left. (Round to two decimal places as needed.) (f) When will there be 15 grams of radioactive material? There will be 15 grams of material left after about weeks. (Round to one decimal place as needed.)