Question:
Mark (✓) against the correct answer:
The surface area of a cube is 384 cm2. Its volume is
(a) 512 cm3
(b) 256 cm3
(c) 384 cm3
(d) 320 cm3
Solution:
(a) $512 \mathrm{~cm}^{3}$
Surface area $=6 a^{2}$
$\Rightarrow 6 a^{2}=384$
$\Rightarrow a=\sqrt{\frac{384}{6}}=\sqrt{64}=8 \mathrm{~cm}$
$\therefore$ Volume $=a^{3}=8^{3}=512 \mathrm{~cm}^{3}$