Y is partly constant and partly varies as x, and when x=5,y=8, and when x=6, y=4, find the equation connecting y and x,
find y when x=15,
find x when y=20

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.