Answer:22.36 mi/hr
Step-by-step explanation:
Given
water in a river moves south at [tex](V_w)10 mi/hr[/tex]
motorboat travels due to east at a speed of [tex](V_b)20 mi/hr[/tex]
Velocity of boat relative to the moving water [tex]V_{bw}[/tex]
[tex]V_{bw}=V_b-V_w[/tex]
[tex]V_{bw}=20i-(-10j)=20i+10j[/tex]
Magnitude of [tex]V_{bw}=\sqrt{20^2+10^2}=\sqrt{500}[/tex]
[tex]V_{bw}=10\sqrt{5} \approx 22.36 mi/hr[/tex]
[tex]tan\theta =\frac{10}{20}[/tex]
[tex]\theta =26.56^{\circ}[/tex] with the x axis.