Ans: B
We sketch a graph according to the question.
We sketch a graph according to the question.
Note that the shortest distance between the lighthouse and the ship is $x\text{ km}$.
$\begin{array}{rcl}
\theta & = & 90^\circ – 60^\circ \\
\theta & = & 30^\circ
\end{array}$
Hence, we have
$\begin{array}{rcl}
\sin \theta & = & \dfrac{x}{50} \\
\sin 30^\circ & = & \dfrac{x}{50} \\
x & = & 50 \sin 30^\circ \\
x & = & 25
\end{array}$
Therefore, the shortest distance between the light house and the ship is $25\text{ km}$.
