Internal length, height, and breadth of an open box are 95 cm, 82 cm, and 75 cm. Thickness of wood is given to be 2.5 cm, calculate the cost of painting outside the box as Rs 1 per dm²

The correct answer is: 384.20

We have given the Internal dimensions of the box
length = 95 cm,
breadth = 75 cm
height = 82 cm
Outer dimensions of the box are
length = 95 + 2  2.5 = 100 cm,
breadth = 75 + 2  2.5 = 80 cm
height = 82 + 2.5 = 84.5 --as the box is open we will add only 2.5
Surface area of the box = 2(lb+ bh +lh)

= 2((95)(75)+(75)(82)+(95)(82))

= 2(8000+6760+8450)=

= 46420 cm²
Surface area of the open box = Total area  - area of open side

= 46420 – (95)(75)

= 46420-8000

= 38420 cm²

= 384.2 dm²

Cost of painting = Rs. 384.20
Therefore option d) 384.20 is correct.