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1.

The top of a 15 metre high tower makes an angle of elevation of 60° with the bottom of an electric pole and angle of elevation of 30° with the top of the pole. What is the height of the electric pole ?

A) 5 metres

B) 8 metres

C) 10 metres

D) 12 metres

E) None of these

2.

A man on the top of a vertical observation tower observes a car moving at a uniform speed coming directly towards it. If it takes 12 minutes for the angle of depression to change from 30° to 45°, how soon after this will the car reach the observation tower ?

A) 14 min. 35 sec.

B) 15 min. 49 sec.

C) 16 min. 23 sec.

D) 18 min. 5 sec.

3.

A man is watching from the top of a tower a boat speeding away from the tower. The boat makes an angle of depression of 45° with the man's eye when at a distance of 60 metres from the tower. After 5'seconds, the angle of depression becomes 30°. What is the approximate speed of the boat, assuming that it is running in still water ?

A) 32 kraph

B) 36 kraph

C) 38 kraph

D) 40 kraph

E) 42 kraph

4.

The angle of elevation of the top of a tower from a certain point is 30°. If the observer moves 20 m towards the tower, the angle of elevation of the top of the tower increases by 15°. The height of the tower is :

A) 17.3m

B) 21.9m

C) 27.3m

D) 30m

5.

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

A) 4 root of 3 units

B) 8 units

C) 12 units