About the numerical question (at 19'24"): The only numbers between 0 and 9 whose cube is a 3 digit number ending with the same number are: 5, 6 and 9, whose cubes are 125, 216 and 729 respectively. If we take the first two digits of these only, in reversed order, to form 2 digit numbers, this gives 21, 12 and 27, and their squares are 441, 144, and 729 respectively. So if the question asked had stipulated this, the correct answer would indeed be 729. But the question asked was not this. Instead it stipulated that: "Reversing the order of its first two digits gives its square root." If this is done, the numbers obtained are 215, 126 and 279, none of which is the square root of the original three digit number. An incorrectly stated question, but nevertheless a correct answer to another question, which was not the one stated! Very curious.... What does this suggest?
About the numerical question (at 19'24"): The only numbers between 0 and 9 whose cube is a 3 digit number ending with the same number are: 5, 6 and 9, whose cubes are 125, 216 and 729 respectively. If we take the first two digits of these only, in reversed order, to form 2 digit numbers, this gives 21, 12 and 27, and their squares are 441, 144, and 729 respectively. So if the question asked had stipulated this, the correct answer would indeed be 729. But the question asked was not this. Instead it stipulated that: "Reversing the order of its first two digits gives its square root." If this is done, the numbers obtained are 215, 126 and 279, none of which is the square root of the original three digit number. An incorrectly stated question, but nevertheless a correct answer to another question, which was not the one stated! Very curious.... What does this suggest?