my answer is different .but I think its correct.what's ur opinion?
Answers
Answer:
Remaining time till car arrives at tower is approx 16.4 minutes.
(i.e. That is the time from when the angle was 45°. The time from the first moment, when the angle was 30°, is 12 minutes longer, so 28.4 minutes.)
Step-by-step explanation:
Let h be the height of the tower,
d be the distance of the car at the start (angle 30°),
e be the distance of the car at the second moment (angle 45°).
Then
tan 30° = h/d => 1/√3 = h/d => d = √3 h
tan 45° = h/e => 1 = h/e => e = h
The distance travelled in 12 minutes is d - e. The speed ( units per minute) is then
v = distance / time = ( d - e ) h / 12 = ( √3 - 1 ) h / 12.
The time remaining till the car arrives at the tower is the time it takes to travel the distance e.
t = distance / speed = e / v minutes
= 12 h / ( √3 - 1 ) h minutes
= 12 / ( √3 - 1 ) minutes
≈ 16.4 minutes