Question

a closed box is made up of 2cm thick wood with external dimensions 84cm*75cm*64cm find the volume of the wood required to make the box

Answer 1

External Dimensions of the CLOSED wooden box :
    L X B X H  =    84 cm  X  75 cm X 64 cm
                      =   403200 cm³

Thickness of the wood used to make the box = 2 cm

Internal dimensions of the closed box :
        L'  =  L - 2 * t   ,  B' = B - 2 t ..      H ' = H - 2 t
         ie.,   84-2*2 = 80cm,     75-2*2 = 71 cm,       64-2*2= 60 cm

Internal volume of the box = 80 cm * 71cm * 60 cm
             = 340, 800 cm³

Volume of wood is the difference between the external and internal volumes. So   :  62, 400 cm³.