Sandra is 20 years older than her son. In 5 years, Sandra’s age will be 3 times her son’s age. How old is Sandra’s son? I need the equation please and thank you.

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.