The internal length, breadth and height of a closed box are 1 m, 80 cm and 25 cm respectively. If its sides are made of 2.5 cm thick wood, find :

(i) the capacity of the box

(ii) the volume of wood used to make the box.

(i) Given:

Outer length of the box = 1 m = 100 cm

Outer width of the box = 80 cm

Outer height of the box = 25 cm

Thickness of wood = 2.5 cm

Internal length = 100 - 2.5 - 2.5 cm = 100 - 5 cm = 95 cm

Internal width = 80 - 2.5 - 2.5 cm = 80 - 5 cm = 75 cm

Internal height = 25 - 2.5 - 2.5 cm = 25 - 5 cm = 20 cm

Volume of internal box = l x b x h

= 95 x 75 x 20 cm³

= 142,500 cm³

Hence, the capacity of the box is 142,500 cm³.

(ii) Volume of box = l x b x h

= 100 x 80 x 25 cm³

= 200,000 cm³

Volume of wood required = Volume of box - Volume of internal box

200,000 - 142,500 cm³

= 57,500 cm³

Hence, the volume of wood required is 57,500 cm³.