Question.
A plastic box 1.5 m long, 1.25 m wide and 65 cm deep, is to be made. It is to be open 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 m2 costs Rs 20.
(i) The area of the sheet required for making the box.
(ii) The cost of sheet for it, if a sheet measuring 1 m2 costs Rs 20.
Solution:
It is given that, length (l) of box = 1.5 m
Breadth (b) of box = 1.25 m
Depth (h) of box = 0.65 m
(i) Box is to be open at top.
Area of sheet required
$=2 h+2 b h+l b$
$=[2 \times 1.5 \times 0.65+2 \times 1.25 \times 0.65+1.5 \times 1.25] \mathrm{m}^{2}$
$=(1.95+1.625+1.875) \mathrm{m}^{2}=5.45 \mathrm{~m}^{2}$
(ii) Cost of sheet per m2 area = Rs 20
Cost of sheet of $5.45 \mathrm{~m}^{2}$ area $=$ Rs $(5.45 \times 20)$
$=\operatorname{Rs} 109$
It is given that, length (l) of box = 1.5 m
Breadth (b) of box = 1.25 m
Depth (h) of box = 0.65 m
(i) Box is to be open at top.
Area of sheet required
$=2 h+2 b h+l b$
$=[2 \times 1.5 \times 0.65+2 \times 1.25 \times 0.65+1.5 \times 1.25] \mathrm{m}^{2}$
$=(1.95+1.625+1.875) \mathrm{m}^{2}=5.45 \mathrm{~m}^{2}$
(ii) Cost of sheet per m2 area = Rs 20
Cost of sheet of $5.45 \mathrm{~m}^{2}$ area $=$ Rs $(5.45 \times 20)$
$=\operatorname{Rs} 109$