Question 98
A wooden box (including the lid) has external dimensions 40 cm×34 cm×30 cm. If the wood is 1 cm thick, how many cm3 of wood is used in it?
External dimensions of wooden box are 40 cm×34 cm×30 cm
Since, the wood is 1 cm thick, it means the internal dimensions will be
(40−2) cm×(34−2) cm×(30−2) cm=38 cm×32 cm×28 cm
∴ Wood used for the box
= Volume of the wooden box with external dimensions - Volume of the wooden box with internal dimensions.
=40×34×30−38×32×28=40800−34048=6752 cm3