Answer:
a) [tex]v_{river} = 1.1\,mph[/tex], b) [tex]v_{person} =4.5\,mph[/tex]
Step-by-step explanation:
Overall speeds up river and down river are modelled by following expressions:
Up River
[tex]-3.4\,mph = v_{river} - v_{person}[/tex]
Down River
[tex]5.6\,mph=v_{river} + v_{person}[/tex]
After some algebraic manipulations, speeds are found:
[tex]v_{river} = 1.1\,mph[/tex]
[tex]v_{person} =4.5\,mph[/tex]