Volume and Surface Area - General Questions
| 1. | How many bricks, each measuring 25 cm x 11.25 cm x 6 cm, will be needed to build a wall of 8 m x 6 m x 22.5 cm? |
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Answer: Option C Explanation: Number of bricks =Volume of the wall= |
800 x 600 x 22.5
= 6400.Volume of 1 brick25 x 11.25 x 6| 2. | 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? |
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Answer: Option C Explanation: Volume of the large cube = (33 + 43 + 53) = 216 cm3. Let the edge of the large cube be a. So, a3 = 216
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a = 6 cm.
Required ratio =| 3. | What is the total surface area of a right circular cone of height 14 cm and base radius 7 cm? |
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Answer: Option C Explanation: h = 14 cm, r = 7 cm. So, l = √(7)2 + (14)2 = √245 = 7√5 cm.
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rl + | 4. | 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: |
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Answer: Option B Explanation: Let the thickness of the bottom be x cm. Then, [(330 - 10) x (260 - 10) x (110 - x)] = 8000 x 1000
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| 5. | The curved surface area of a cylindrical pillar is 264 m2 and its volume is 924 m3. Find the ratio of its diameter to its height. |
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Answer: Option B Explanation:
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| 6. | 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: |
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Answer: Option B Explanation: Clearly, l = (48 - 16)m = 32 m, b = (36 -16)m = 20 m, h = 8 m.
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| 7. | A cistern 6m long and 4 m wide contains water up to a depth of 1 m 25 cm. The total area of the wet surface is: |
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Answer: Option A Explanation:
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| 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. |
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Answer: Option C Explanation: l = 10 m, h = 8 m. So, r = l2 - h2 = (10)2 - 82 = 6 m.
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