Question

Find the volume of wood used to make a closed box of outer dimensions 60 cm × 45 cm × 32 cm, the thickness of wood being 2.5 cm all around.

Answer 1

External length = 60 cm
External width = 45 cm
External height = 32 cm

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

Thickness of wood = 2.5 cm

∴ Internal length $=60-(2.5\times 2)=55$ cm
Internal width $=45-(2.5\times 2)=40$ cm
Internal height $=32-(2.5\times 2)=27$ cm

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

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