Question

213
EXERCISE 13.1
1. 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:
(1) The area of the sheet required for making the box.
w The cost of sheet for it, if a sheet measuring Im’ costs 20.
oth breadth and height of with full solution​

Answer 1

Answer:

Here we are given that

(i) Length of plastic box (l) = 1.5 m

Breadth of plastic box (b) = 1.25 m

Height of plastic box (h) = 65 cm 

= 0.65 m

Since box is open at the top. 

Therefore total surface area  of the plastic box (open at the top)

= lb + 2bh + 2hl

= [1.5 x 1.25 + 2(1.25 x 0.65 + 0.65 x 1.5)]

m2 = [1.875 + 2(0.8125 + 0.975)]

m2 = [1.875 + 2 x 1.7875]

m2 = [1.875 + 3.575]

m2 = 5.450 m2

Hence, area of the plastic sheet required for making the box is 5.450 m2.

(ii) Cost of 1 m2 plastic sheet = Rs. 20

Cost of 5.45 m2 plastic sheet 

= Rs. 5.540 x 20

 = Rs. 109