River is flowing with a velocity ${\overrightarrow{v}}_R=4\hat{i} m/s$. A boat is moving with a velocity of ${\overrightarrow{v}}_{BR}=\left(-2\hat{i}+4\hat{j}\right) m/s$ relative to river. the width of the river is $100 m$ along $y-$ direction. Choose the correct alternative (s).