NTA Abhyas JEE Main2020MathematicsHeights and DistancesPractice
A chimney of 20 m height standing on the top of a building subtends an angle whose tangent is 1 6 at a distance of 70 m from the foot of the building, then the height of building is
Options
- A50 m
- B25 m
- C75 m
- D100 m
Correct answer
A. 50 m
Step-by-step solution
Given, tan α = 1 6 tan α + β = tan α + tan β 1 - tan α tan β h + 20 70 = 1 6 + h 70 1 - 1 6 ⋅ h 70 h + 20 70 = 70 + 6 h 420 - h ⇒ h = 50 Hence, 50 m is correct choice.