Buford, the farm hand, is preparing feed for the animals. He wants to mix the contents of a bag containing 50% corn with one containing 90% corn to obtain a 30-pound bag containing 80% corn. How many pounds of the 50% bag should he use? (Write your answer as a decimal.)

David estimated he had about 20 fish in his pond. a year later, there were about 1.5 times as many fish. the year after that, the number of fish increased by a factor of 1.5 again. the number of fish is modeled by f(x)=20(1.5)^x. create a question you could ask that could be answered only by graphing or using a logarithm.