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Home Aptitude Height and Distance See What Others Are Saying!
  • Question
  • A man on the top of a vertical towers observes a car moving at a uniform speed coming directly towards it. if it takes 12 minute for the angle of depression to change from 30° to 45°, how soon after this will the car reach the tower?


  • Options
  • A. 14 min 20 sec.
  • B. 15 min 22 sec.
  • C. 16 min.
  • D. 16 min 23 sec.

  • Correct Answer
  • 16 min 23 sec. 

    Explanation

    Let us draw a figure below from given question.
    Let AB = h meter be the height of the tower B and C are two points such that ?ACB = 30° ?ADB = 45° and CD = x meter (say)
    From right triangle ABD,
    tan 45° = h/BD
    ? BD = h meter;
    Again from right triangle ABC
    tan 30° = h/(h + x )
    ? h + x = ?3 h
    ? x = (1.73 - 1)h = 0.73h
    Now, 0.73h meter covered in 12 min
    Hence, h meter covered in 12/0.73 = 1200/73 min = 16 min 23 sec .


  • More questions

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      The value of 47 / 10000 is?

    • Options
    • A. .0047
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    • D. .000047
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    • 2. If 4x = 18y, then the value of ( x/y - 1) is

    • Options
    • A. 1 3
    • B. 7 2
    • C. 2 3
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    • 3. 
      If the price of 23 toys is Rs. 276, then what will the price (Rs.) of 12 toys?

    • Options
    • A. 144
    • B. 158
    • C. 159
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    • 4. 
      .02 =(......?.....)%

    • Options
    • A. 20
    • B. 2
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    • 5. 
      If 36 men can do a piece of work in 25 hours, in how many hours will 15 men do it?

    • Options
    • A. 45
    • B. 55
    • C. 60
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    • 6. 
      2?63 / 11 =233

    • Options
    • A. 4
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    • C. 6
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    • 7. 
      When 121012 is divided by 12, the remainder is

    • Options
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    • 8. 
      Aarti can do a piece of work in 6 days. In how many days will she complete three time of work of same type?

    • Options
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    • Discuss
    • 9. 
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    • Options
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    • Discuss
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      105, 85, 60, 30, 0, - 45, - 90?

    • Options
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