8. Prehistoric cave paintings were discovered in a cave in France. The paint contained 11% of the original carbon-14. Use the exponential decay model for carbon-14, A = Ape 0.000121, to estimate the age of the paintings. Paper size |Letter V Print The paintings are approximately years old. (Round to the nearest integer.) Complete the table shown to the right for the half-life of a certain radioactive substance. Half-Life Decay Rate, k 9.9% per year = - 0.099 The half-life is years . (Round to one decimal place as needed.) Complete the table shown to the right for the half-life of a certain radioactive substance. Half-Life Decay Rate, k 14.8 days K = (Round to six decimal places as needed.) 11. The half-life of a certain tranquilizer in the bloodstream is 20 hours. How long will it take for the drug to decay to 95% of the original dosage? Use the exponential decay model, A = Apekt, to solve. hours (Round to one decimal place as needed.) Use the exponential growth model, A = Agent, to show that the time it takes a population to double (to grow from A to 2A) is given by t= - K To find the time it takes to grow the population from Ap to 2Ap, substitute A = (1) = Apekt Substitute . Divide both sides by Ap. Take the natural logarithm on both In 2 = In sides. In 2 = Simplify. In 2 Isolate t. (1) 0 2 40 . O 2 O AO