Question:
A cuboid has total surface area of 50 m2 and lateral surface area is 30 m2. Find the area of its base.
Solution:
Total sufrace area of the cuboid $=50 \mathrm{~m}^{2}$
Its lateral surface area $=30 \mathrm{~m}^{2}$
Now, total surface area of the cuboid $=2 \times($ surface area of the base $)+($ surface area of the 4 walls $)$
$\Rightarrow 50=2 \times($ surface area of the base $)+(30)$
$\Rightarrow 2 \times($ surface area of the base $)=50-30=20$
$\therefore$ Surface area of the base $=\frac{20}{2}=10 \mathrm{~m}^{2}$