Camila has $0.90 worth of nickels and dimes. She has 7 times as many nickels as dimes. By following the steps below, determine the number of nickels, x , x, and the number of dimes, y , y, that Camila has.

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.