Brock is a plumber. he charges a flat rate of $40 to visit a house to inspect it's plumbing. he charges an additional $20 for every hour he spends inspecting or making repairs. which graph below correctly shows the price of using brock's plumbing service vs time?

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.