A man standing at a point P is watching the top of a tower, which makes an angle of elevation of 30º with the man’s eye. The man walks some distance towards the tower to watch its top and the angle of the elevation becomes 60º. What is the distance between the base of the tower and the point P?

a) 4 √3 units
b) 8 units
c) 12 units
d) Data inadequate

Answer: d
Explanation: One of AB, AD and CD must have given.

So, the data is inadequate.