NextMockSearch exams, e.g. SSC CGL, UPPSC, Lekhpal
Railways PYQCBT 1 2016

RRB NTPC · Question 92

The shadow of a tower on ground level is increased by 30 m, when the angle of depression by the sun changes from 60° to 30°. The height of the tower is?

  1. 12√3 m

  2. 17√3 m

  3. 16√3 m

  4. 15√3 m

Show answer & explanation

Answer: (D) 15√3 m

Explanation

Let the height be h. At 60° the shadow is h/√3; at 30° it is h√3. The increase is h√3 − h/√3 = 2h/√3 = 30, so h = 15√3 m.