You put $500 in the bank, where it earns 1.5% simple interest each year. How long until your money will triple? Pls hurry awnser only if you know

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.