doctor prescribes 100 milligrams of a therapeutic drug that decays by about 20% each hour (ie. after 1 hour, 20% of the drug is gone). Assume the quantity of the drug is modeled by an exponential equation. What is the half-life of the drug? Please use a calculator to compute the final answer and round down to two decimal plac

40 grams of radioactive material decays to 35 grams in 20 years. Find the half-life. 5

The population of a colony of bacteria decreases exponentially, decreasing by 30% every three hours. The population is 240, 000 at noon. Find the population when it is decreasing at the rate of 50, 000 bacte- ria/hour. Express your answer in its simplest form. Do not use a calculator. Then, at the very end, use a calculator to compute the population.

The count in a bacteria culture was 600 after 20 minutes and 2000 after 30 minutes. Assuming the count grows exponentially, What was the initial size of the culture? Find the doubling period. Find the population after 110 minutes. When will the population reach 14000.