Question

a chimney of 20m height standing on the top of a building subtends an angle whose tangent is 1/6 at a distance of 70m from the foot of the building find the height of the building .

Answer 1

(20 + height)/70 = tanØ = 1/6
120 + 6height = 70
6 height = -50
height can't be negative

Check your typing, the question makes no sense
(I read it that the tan of the subtended angle is 1/6)