Exponential Growth and Decay Word Problems Half-Life Problems 1. A hospital prepares a 100mg supply of technetium-99m which has a half-life of 6 hours. a. What is the decay factor? b. What is the length of a half-life? C. Write an equation to represent this problem. d. Find the amount of technetium-99m that remains after 75 hours. 2. Arsenic-74 is used to locate brain tumors. It has a half-life of 17.5 days. a. What is the decay factor? e. What is the length of a half-life? b. Write an equation to represent this problem. c. Find the amount remaining after 6 days from a 90-mg sample. 3. Phosphorus-32 is used to study a plant's use of fertilizer. It has a half-life of 14.3 days. Write the exponential decay function for a 50- mg sample. Find the amount of phosporus-32 remaining after 84 days. Exponential Growth and Decay Word Problems 4. Iodine-131 is used to find leaks in water pipes. It has a half-life of 8.14 days. Write the exponential decay function for a 200-mg sample. Find the amount of Iodine-131 remaining after 72 days. 5 . Carbon-14 is used to determine the age of artifacts in carbon dating. It has a half-life of 5730 years. Write the function for a 24- mg sample. Find the amount remaining after 30 millennia (1 millennium = 1,000 years) 6. Hg-197 is used in kidney scans. It has a half-life of 64.128 h. Write the exponential decay function for a 12-mg sample. Find the amount remaining after 72 h. 7. Sr-85 is used in bone scans. It has a half-life of 64.9 days. Write the exponential decay function for an 8-mg sample. Find the amount remaining after 100 days. 8. I-123 is used in thyroid scans. It has a half-life of 13.2 h. Write the exponential decay function for a 45-mg sample. Find the amount remaining after 5 h