COMEDK2016MathematicsHeights and Distances
From an aeroplane flying, vertically above a horizontal road, the angles of depression of two consecutive stones on the same side of the aeroplane are observed to be 30^ and 60^ respectively. The height at which the aeroplane is flying in km , is
Options
- A2
- B2 3
- C3 2
- D4 3
Correct answer
C. 3 2
Step-by-step solution
Let the distance of two consecutive stones are (x, x+1) . In B C D , we have 60^ = h x x= h 3 ...(i) In A B C , we have 30^ = h x+1 1 3 = h x+1 h 3 +1= 3 h [by Eq. (i)] array ll & h ( 3 - 1 3 )=1 & h ( 2 3 )=1 h= 3 2 array