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Home Aptitude Volume and Surface Area Comments

  • Question
  • A hollow iron pipe is 21 cm long and its external diameter is 8 cm. If the thickness of the pipe is 1 cm and iron weighs 8 g/cm3, then the weight of the pipe is:


  • Options
  • A. 3.6 kg
  • B. 3.696 kg
  • C. 36 kg
  • D. 36.9 kg

  • Correct Answer
  • 3.696 kg 

    Explanation
    External radius = 4 cm,

    Internal radius = 3 cm.

    Volume of iron
    = 22 x [(4)2 - (3)2] x 21 ❩cm3
    7
    = 22 x 7 x 1 x 21 ❩cm3
    7
    = 462 cm3.

    ∴ Weight of iron = (462 x 8) gm = 3696 gm = 3.696 kg.


  • Volume and Surface Area problems


    Search Results


    • 1. A large cube is formed from the material obtained by melting three smaller cubes of 3, 4 and 5 cm side. What is the ratio of the total surface areas of the smaller cubes and the large cube?

    • Options
    • A. 2 : 1
    • B. 3 : 2
    • C. 25 : 18
    • D. 27 : 20
    • Discuss
    • 2. A cistern of capacity 8000 litres measures externally 3.3 m by 2.6 m by 1.1 m and its walls are 5 cm thick. The thickness of the bottom is:

    • Options
    • A. 90 cm
    • B. 1 dm
    • C. 1 m
    • D. 1.1 cm
    • Discuss
    • 3. A hall is 15 m long and 12 m broad. If the sum of the areas of the floor and the ceiling is equal to the sum of the areas of four walls, the volume of the hall is:

    • Options
    • A. 720
    • B. 900
    • C. 1200
    • D. 1800
    • Discuss
    • 4. 66 cubic centimetres of silver is drawn into a wire 1 mm in diameter. The length of the wire in metres will be:

    • Options
    • A. 84
    • B. 90
    • C. 168
    • D. 336
    • Discuss
    • 5. 50 men took a dip in a water tank 40 m long and 20 m broad on a religious day. If the average displacement of water by a man is 4 m3, then the rise in the water level in the tank will be:

    • Options
    • A. 20 cm
    • B. 25 cm
    • C. 35 cm
    • D. 50 cm
    • Discuss
    • 6. In a shower, 5 cm of rain falls. The volume of water that falls on 1.5 hectares of ground is:

    • Options
    • A. 75 cu. m
    • B. 750 cu. m
    • C. 7500 cu. m
    • D. 75000 cu. m
    • Discuss
    • 7. A metallic sheet is of rectangular shape with dimensions 48 m x 36 m. From each of its corners, a square is cut off so as to make an open box. If the length of the square is 8 m, the volume of the box (in m3) is:

    • Options
    • A. 4830
    • B. 5120
    • C. 6420
    • D. 8960
    • Discuss
    • 8. The slant height of a right circular cone is 10 m and its height is 8 m. Find the area of its curved surface.

    • Options
    • A. 30Π m2
    • B. 40Π m2
    • C. 60Π m2
    • D. 80Π m2
    • Discuss
    • 9. 8988 ÷ 8 ÷ 4 =?

    • Options
    • A. 4494
    • B. 561.75
    • C. 2247
    • D. 280.875
    • E. None of these
    • Discuss
    • 10. 5358 x 51 =?

    • Options
    • A. 273258
    • B. 273268
    • C. 273348
    • D. 273358
    • Discuss


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