Q30 of 47 Page 1

A man observes a car from the top of a tower, which is moving towards the tower with a uniform speed. If the angle of depression of the car changes from 30° to 45° in 12 minutes, find the time taken by the car now to reach the tower.


Given ∠ADB=30° and ∠ACB= 45


Let height of tower AB = h


Let speed of car = v


Let time = t


Distance = vt


In ∆ABC





In ∆ABD











Conclusion: Therefore, time taken to reach the tower is 16.43 minutes


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