(A) A straight highway leads to the foot of a tower. A man standing on the top of the $75\mathrm{m}$ high tower observes two cars at angles of depression of ${30}^{\circ }$ and ${60}^{\circ }$ , which are approaching the foot of the tower. If one car is exactly behind theother on the same side of the tower, find the distance between the two cars. (use $\sqrt{3}=1.73$ )

OR
(B) From the top of a $7\mathrm{m}$ high building, the angle of elevation of the top of a cable tower is ${60}^{\circ }$ and the angle of depression of its foot is ${30}^{\circ }$. Determine the height of the tower.