As observed from the top of a $75 \mathrm{m}$ high lighthouse from the sea-level, the angles of depression of two ships are $30°$ and $45°$. If one ship is exactly behind the other on the same side of the lighthouse, find the distance between the two ships.

A $1.2 \mathrm{m}$ tall girl spots a balloon moving with the wind in a horizontal line at a height of $88.2 \mathrm{m}$ from the ground. The angle of elevation of the balloon from the eyes of the girl at any instant is $60°$. After some time, the angle of elevation reduces to $30°$ (see Fig.). Find the distance travelled by the balloon during the interval.

A straight highway leads to the foot of a tower. A man standing at the top of the tower observes a car at an angle of depression of $\mathrm{}{30}^{\mathrm{o}}$, which is approaching the foot of the tower with a uniform speed. Six seconds later, the angle of depression of the car is found to be $\mathrm{}{60}^{\mathrm{o}}$.

Find the time taken by the car to reach the foot of the tower from this point.