Question

A closed wooden box has outer dimensions as 10cm ×8cm×7cm.The thickness of wood is 1 cm.If 1 cu.metres of wood costs rs .2 ,find the amount needed to make the box..

Answer 1

Length , l = 10 cm
Breadth , b = 8 cm
Height , h = 7 cm
Total volume of the cuboid = lbh
= 10 cm ×8 cm×7 cm
= 560 cm³

As the wood is 1 cm³ thick , we need to subtract 1 cm³ from each dimension of the cuboid.


length = 10 - 1 = 9 cm³
breadth = 8 - 1 = 7 cm³
height = 7 - 1 = 6 cm ³

Inner Volume the cuboid = l b h
= 9 × 7 × 6
= 378 cm³

Volume of wood = Total volume of the cuboid - Inner Volume the cuboid
= 560 cm³ - 378 cm³
= 182 cm³ = 0.000182 m³

Cost of wood for 1 m³ = Rs 2
Cost of wood for 0.000182 m³ = 0.000182 m³× 2
= Rs 0.000364