The resultant velocity is the vector sum of the two velocity vectors.
Let the boat move east (x-axis) so that its velocity is
[tex](8.0 \, m/s)\hat{i}[/tex]
Let the river flow north (y-axis), so that its velocity is
[tex](6.0 \, m/s)\ht{j}[/tex]
The magnitude of the resultant velocity is
[tex]v= \sqrt{8^{2}+6^{2}} =10 \, m/s[/tex]
Answer: 10 m/s
