Question

Question 3(ii)
Find the smallest number by which each of the following numbers must be divided to obtain a perfect cube:
128

Answer 1

128
Prime factors of $128=2\times 2\times 2\times 2\times 2\times 2\times 2$
Here one factor 2 does not appear in a 3’s group.
Therefore, 128 must be divided by 2 to make it a perfect cube.
$\begin{array}{cc}2& 128\\ 2& 64\\ 2& 32\\ 2& 16\\ 2& 8\\ 2& 4\\ 2& 2\\ & 1\end{array}$