Question

A closed box is made up of wood which is 1 cm thick .the outer dimensions of the box 5cm,4 cm,7 cm.find the volume of wood used

Answer 1

therefore
External volume=5cm
External breadth= 4cm
External height=7cm

therefore external volume of the box=(5×4×7)cm
=140cm cube

therefore

internal length = 5-(2+2)=1
internal breadth=4-(2+2)0
internal height=7-(2+2)=3

therefore
internal volume = 1×0×3
= 3cm cube

therefore
volume of the wood = external volume-internal volume

=140-3
=137cm cube