Q.

Find the cube root of 46656 by finding their units and ten digits.


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a

  32

b

  34

c

  36

d

  38 

answer is C.

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Detailed Solution

Concept- We will have to observe the unit’s digit of the given number, and think of a number out of [0, 1 ,2, 3, 4, 5, 6, 7, 8, 9] whose cube will have the same digit as the unit’s digit. Then, we have to hide 3 digits from the left and consider the first 2 digits of the number. Then we need to think of a number whose cube will be less than the number given in the question. In 46656, the last digit or the unit’s digit is 6. And out of [0, 1 ,2, 3, 4, 5, 6, 7, 8, 9], Only 6 is such a number whose unit’s digit of cube, is 6, i.e.,
https://lh6.googleusercontent.com/Mf3ZAXUCQX2wKp0EDddr8HCW8RcU3PL-_QSgXZpUJC3bZevHI1fO1xN6rVZJzbkqNJQdhNFQRG9qbuoS4kApl1dVjl51nEO284W9suIqnp39BPdc7Iykg5ZCedRrrzHTD-VFEOZYN6LhO8AgVQTherefore, the unit's digit of the cube root number is 6.
Now, after hiding 3 digits from the left and considering the first 2 digits of the number 46656, we get 46.
Now, we need to think of a number whose cube will be less than 46.
https://lh4.googleusercontent.com/M4Iy82Ka2C-r4AgIKz5q7U0oH0Y5zGiutD6QJYSpS-7rJeybK994FtLZjBb8IEwJF-IYCF4Pgu02cczpyApVhJmSfi-PF_n8u5j_0bh_iS7SvrJlx0MUoNA8rjWr3XwXuGwqdRUnvD3TarjKmwTherefore, the tens place digit of the cube root number of 46656 is 3.
Therefore, the cube root of 46656 = 36.
Hence, the correct answer is 3) 36.
 
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