Question

A closed box is cuboid in shape with length = 40 cm, breadth = 30 cm and height = 50 cm. It is made of metal sheet. Find the cost of metal sheet required to make 20 such boxes, if $1m^3$ of metal sheet costs Rs 45.

Answer 1

We need to calculate the total surface area of the cuboid to solve this question.
Total surface area of a cuboid of length l, breadth b and height h $=2(l\times b+b\times h+l\times h)$

So, the total surface area of the cuboid $=50cm=2(40\times 30+30\times 50+40\times 50)$

$=2(1200+1500+2000)=9400{cm}^2$

Total surface area of 20 boxes $=20\times 9400{cm}^2=188000{cm}^2=18.8m^2$

Total cost $=Rs45\times 18.8m^2=Rs846$