waecmaths question:
What is the length of an edge of a cube whose total surface is X cm2 and whose volume is $\tfrac{x}{2}c{{m}^{2}}$
Option A:
3
Option B:
6
Option C:
9
Option D:
12
waecmaths solution:
$\begin{align} & \text{Total surface of a cube }=6{{l}^{2}}={{X}^{2}} \\ & Volume=V={{l}^{3}}=\frac{x}{2}cm \\ & \frac{V}{A}=\frac{{{l}^{3}}}{6{{l}^{2}}}=\frac{\tfrac{x}{2}}{x} \\ & \frac{l}{6}=\frac{1}{2} \\ & l=\frac{6}{2}=3cm \\\end{align}$
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