Find the volume of wood used to make a closed box of outer dimensions 60 cm × 45 cm × 32 cm,

External length $=60 \mathrm{~cm}$

External width $=45 \mathrm{~cm}$

External height $=32 \mathrm{~cm}$

External volume of the box $=60 \times 45 \times 32=86400 \mathrm{~cm}^{3}$

Thickness of wood $=2.5 \mathrm{~cm}$

$\therefore$ Internal length $=60-(2.5 \times 2)=55 \mathrm{~cm}$

Internal width $=45-(2.5 \times 2)=40 \mathrm{~cm}$

Internal height $=32-(2.5 \times 2)=27 \mathrm{~cm}$

Internal volume of the box $=55 \times 40 \times 27=59400 \mathrm{~cm}^{3}$

Volume of wood $=$ External volume $-$ Internal volume $=86400-59400=27000 \mathrm{~cm}^{3}$