1.

125 small but identical cubes have been put together to form a large cube. How many such small cubes will be required to cover this large cube completely?1. 2082. 2123. 2544. 218

Answer» Correct Answer - Option 4 : 218
The correct answer is 218.
Let us interpret all the options as per the given information:
  • First option:
    • It is given that 125 small but identical cubes have been put together to form a large cube
    • If we add 208 more cubes, the total number of cubes becomes 333.
    • 333 is not a perfect cube.
    • It is short of 10 more cubes to form a perfect cube.
    • If we add 10 more cubes, then the total becomes 343 which is a perfect cube.
    • Hence, the first option is incorrect.
  • Second option:
    • It is given that 125 small but identical cubes have been put together to form a large cube
    • If we add 212 more cubes, the total number of cubes becomes 337.
    • 337 is not a perfect cube.
    • It is short of 6 more cubes to form a perfect cube.
    • If we add 6 more cubes, then the total becomes 343 which is a perfect cube.
    • Hence, the second option is incorrect.
  • Third option:
    • It is given that 125 small but identical cubes have been put together to form a large cube
    • If we add 254 more cubes, the total number of cubes becomes 379.
    • 379 is not a perfect cube.
    • It is short of 133 more cubes to form a perfect cube.
    • If we add 133 more cubes, then the total becomes 512 which is a perfect cube.
    • Hence, the third option is incorrect.
  • Fourth option:
    • It is given that 125 small but identical cubes have been put together to form a large cube
    • If we add 218 more cubes, the total number of cubes becomes 343.
    • 343 is a perfect cube.
    • Thus, we will be able to form a perfect cube from the given 125 identical cubes if we add 218 more cubes to it.
    • Hence, the fourth option is correct.
Hence, the correct answer is 218.


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