Cube of a number-Solution

Question

Solution:
The smallest 10 digit no starts with 1 and is followed by 9 zeroes. When we take the cube of it, we get a 28 digit no.

Also, the smallest 11 digit no. starts with 1 and is followed by 10 zero's. When we take the cube of it, we get a 31 digit no.

Hence, the no. of digits in the cube root of a 29 digit number should be b) 10.