A plastic box 1.5 m long, 1.25 m wide and 65 cm deep is to be made. It is opened at the top. Ignoring the thickness of the plastic sheet, determine:
i) The area of the sheet required for making the box.
ii) The cost of sheet for it, if a sheet measuring 1\({m}^2\) costs Rs.20.

Given :
length (l) of box = 1.5m
Breadth (b) of box = 1.25 m
Depth (h) of box = 0.65 m

i) Box is to be open at top,
So, Area of sheet required
= 2lh + 2bh + lb
\( = [2 x 1.5 x 0.65 + 2 x 1.25 x 0.65 + 1.5 x 1.25] \)
= [1.95 + 1.625 + 1.875] \({m}^2\)
= 5.45 \({m}^2\)
Hence, the area of the sheet required for making the box is 5.45 \({m}^2\)

ii) Cost of sheet per 1 \({m}^2\) area = Rs.20
Therefore, Cost of sheet of 5.45 \({m}^2\) area
= Rs. (5.45 x 20)
= Rs. 109

Hence, The cost of sheet for it is Rs. 109