In a geometric sequence {an}, if a1 = 4 and r = 0.2, the first 4 terms in the sequence are a) {4, .8, .16, .}. eliminate b) {4, 20, 100, }. c) {4, 4.2, 4.4, 4.}. d) {4, 3.8, 3.6, 3.}.

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.