Question

The inner dimensions of a closed wooden box are 2 m, 1.2 m and 75 m. The thickness
of the wood is 2.5 cm. Find the cost of wood required to make the box if 1 m3 of wood
costs 5400.​

Answer 1

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Given

Inner dimensions of wooden box are 2m by 1.2m by 0.75m

Thickness of the wood =2.5cm= 100\2.5m=0.025 m

Now

External dimensions of wooden box are

=(2+2×0.025) by (1.2+2×0.025) by (0.75+2×0.025)

=(2+0.05) by (1.2+0.05) by (0.75+0.5)

=2.05 by 1.25 by 0.80

Thus

Volume of solid = External volume of box - Internal volume of box

=2.05×1.25×0.80m^3 −2×1.2×0.75m^3

=2.05−1.80=0.25m^3

Given, the cost of wood =Rs 5400 for 1m^3

Hence, Total cost =Rs 5400×0.25=Rs 5400× 100/25 =Rs 54×25=Rs 1350