Question

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 7m×3.5m costsर 510.

Answer 1

Answer:

i) The area of the sheet required for making the box is 5.45 meter square.

ii) The cost of sheet is Rs. 113.447.

Step-by-step explanation:

Given : 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.

To find :

(i) The area of the sheet required for making the box.

(ii) The cost of sheet for it, if a sheet measuring 7m×3.5m costsर 510.

Solution :

i) The dimension of the box is

Length l= 1.5 m

Breadth b= 1.25 m

Height h= 65 cm = 0.65 m

Area of the sheet required is

$A=2lb+2bh+2lh$

$A=2(1.5)(1.25)+2(1.25)(0.65)+2(1.5)(0.65)$

$A=1.95+1.625+1.875$

$A=5.45m^2$

The area of the sheet required for making the box is 5.45 meter square.

ii) The cost of sheet for it, if a sheet measuring 7m×3.5m costsर 510.

i.e, area of sheet 24.5 meter square cost Rs.510

So, 1 meter square cost $\frac{510}{24.5}=20.816$

Now, The cost of 5.45 meter square cost

$20.816\times 5.45=113.447$

Therefore, The cost of sheet is Rs. 113.447.

Answer 2

Given:

Length of box =1.5 m, Breadth =1.25 m, Height =0.65 m

⇒Area to be white-washed = Area of cuboid − Area of base.

(i) Area of sheet requred =2lb+2bh+2lh−lb

(i) Area of sheet requred =2lh+2bh+lb .....[Box is open]

=[2×1.5×0.65+2×1.25×0.65+1.5×1.25] m

2

=(1.95+1.625+1.875)m

2

=5.45 m

2

ii) Cost of sheet per m

2

area = Rs. 20

Cost of sheet of 5.45m

2

area = Rs. 5.45×20

= Rs. 109