Ex 13.1, 1
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.
Given that length (l) of box = 1.5 m
Breadth (b) of box = 1.25 m
Depth (h) of box = 65 cm = 65/100 m = 0.65 m
Area of sheet required = Area of cuboid Area of top which is open
= 2(lb + bh + lh) lb
= 2(lb) + 2(bh) + 2(lh) lb
= lb + 2(bh) + 2(lh)
= [1.5 1.25 + 2 1.25 0.65 + 2 1.5 0.65 ] m2
= (1.95 + 1.625 + 1.875) m2
= 5.45 m2
Ex 13.1, 1
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:
(ii) The cost of sheet for it, if a sheet measuring 1 m2 costs Rs 20.
Area of sheet required = 5.45 m2
Cost of sheet per 1 m2 area = Rs 20
Cost of sheet of 5.45 m2 area = Rs (5.45 20)
= Rs 109

Made by

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.