Question:
The external dimensions of a closed wooden box are 62 cm, 30 cm and 18 cm. If the box is made of 2-cm-thick wood, find the capacity of the box.
Solution:
External length $=62 \mathrm{~cm}$
External width $=30 \mathrm{~cm}$
External height $=18 \mathrm{~cm}$
$\therefore$ External volume of the box $=62 \times 30 \times 18=33480 \mathrm{~cm}^{3}$
Thickness of the wood $=2 \mathrm{~cm}$
Now, internal length $=62-(2 \times 2)=58 \mathrm{~cm}$
Internal width $=30-(2 \times 2)=26 \mathrm{~cm}$
Internal height $=18-(2 \times 2)=14 \mathrm{~cm}$
$\therefore$ Capacity of the box $=$ internal volume of the box $=(58 \times 26 \times 14) \mathrm{cm}^{3}=21112 \mathrm{~cm}^{3}$