17. The half-life of the radioactive element plutonium-239 is 25,000 years. If 16 grams of plutonium-239 are initially present, how many grams are present after: (round your answer to the nearest hundredth) Find the exponential model first. a. 25,000 years b. 50,000 years t = 25,000 A = Pekt P = 14 K (25 8=16 A = 8 16 16 e. 125,000 years k = /1\/2 25000 c. 75,000 years d. 100,000 years