CAT Practice : Trigonometry

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Max and Min value of the given expression

Height and Distances

    Q.9: A man standing on top of a tower sees a car coming towards the tower. If it takes 20 minutes for the angle of depression to change from 30° to 60°, what is the time remaining for the car to reach the tower?
    1. 20√3 minutes
    2. 10 minutes
    3. 10√3 minutes
    4. 5 minutes


  • Correct Answer
    Choice B. 10 minutes

Explanatory Answer

Detailed Solution

From the figure:-

tan 30° =

tan 60° =

=) a + b = 3b

=) 2b = a

=) b =

Now since the car takes 20 minutes to travel a distance

Time taken to travel b = distance =) = 10 minutes

Answer choice (B)

Correct Answer: 10 minutes

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