logo

CuriousTab

CuriousTab

Discussion


Home Aptitude Height and Distance See What Others Are Saying!
  • Question
  • On the ground level the angle of elevation of the top of a tower is 30°, On moving 20 m nearer the tower, the angle of elevation found to be 60°. The height of the tower is?


  • Options
  • A. 10 m
  • B. 10?3 m
  • C. 15 m
  • D. 20 m

  • Correct Answer
  • 10?3 m 

    Explanation

    Let us draw a figure below from the given question.
    Let AB = h meter be the height of the towers. B and C are two points such that BC = 20 m; ?ADB = 30° and ?ACB = 60° BC = x meter (let us assume)
    Now, from right triangle ABC,
    x = h cot 60°
    ? x = h/?3 meter
    Again, from right triangle ABD,
    h = (20 + x) tan 30°
    put the value of x in above equation.
    ? x = h/?3
    ? h = (20 + h/?3) x 1/?3 ( ? tan 30° = 1/?3 )
    ? h - h/3 = 20/?3 ? 2h/3 = 20/?3
    ? h = 20 x 3/2?3 = 10?3 m


  • More questions

    • 1. 
      ?. x 4 ? 227 = 398
      ?. y 2 + 321 = 346

    • Options
    • A. 1
    • B. 2
    • C. 3
    • D. 4
    • Discuss
    • 2. If 6th March, 2005 is Monday, what was the day of the week on 6th March, 2004?

    • Options
    • A. Sunday
    • B. Saturday
    • C. Tuesday
    • D. Wednesday
    • Discuss
    • 3. 1, 4, 9, 16, 23, 25, 36

    • Options
    • A. 9
    • B. 23
    • C. 25
    • D. 36
    • Discuss
    • 4. 
      A sum of money is to be divided equally among P, Q and R in the respective ratio of 5 : 6 : 7 and another sum of money is to be divided between S and T equally. If S got ? 2100 less than P, then how much amount did Q receive?

    • Options
    • A. ? 2500
    • B. ? 2000
    • C. ? 1500
    • D. Couldn't be determined
    • Discuss
    • 5. 
      If a : b = b : c, then ratio a 4 : b 4 is equal to

    • Options
    • A. ac : b2
    • B. a2 : c2
    • C. c2 : a2
    • D. b2 : ac
    • Discuss
    • 6. 
      A man covers half of his journey at 6 km/h and the remaining half at 3 km/h. Find his average speed.

    • Options
    • A. 3 km/h
    • B. 4 km/h
    • C. 4.5 km/h
    • D. 9 km/h
    • Discuss
    • 7. 
      A person can walk a certain distance and drive back in 6 h. He can also walk both ways in 10 h. How much time will he take to drive both ways?

    • Options
    • A. 2 h
    • B. 21/2 h
    • C. 51/2 h
    • D. 4 h
    • Discuss
    • 8. 
      Find the least number by which 175760 be devided to make it a perfect cube.

    • Options
    • A. 10
    • B. 20
    • C. 100
    • D. 5
    • Discuss
    • 9. 
      The roots of the equation x2 + px + q = 0 are equal if :

    • Options
    • A. p2 = 2q
    • B. p2 = 4q
    • C. p2 = - 4q
    • D. p2 = - 2q
    • Discuss
    • 10. 
      Two cubes have volumes in the ratio 1: 27, The ratio of their surface areas is?

    • Options
    • A. 1 : 3
    • B. 1 : 8
    • C. 1 : 9
    • D. 1 : 18
    • Discuss


    Comments

    There are no comments.

Enter a new Comment