At eugene's printing company llc there are two kinds of printing presses: model a which can print 40 books per day and model b which can print 70 books per day. the company owns 13 total printing presses and this allows them to print 820 books per day. how many of each type of press do they have?

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.