Question

A plastic box 1.5 metre 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 2. the cost of the sheet for it if a sheet measuring 1 metre² cost ₹ 20​

Answer 1

Step-by-step explanation:

Given, l = 1.5 m, b = 1.25 m, h = 65 cm = 0.65 m.  

Since the box is open at the top, it has only five faces.

(i)

So, surface area of the box = lb + 2(bh + hl)  

= 1.5 × 1.25  + 2 (1.25 × 0.65 + 0.65 × 1.5)

= 1.875 + 2 (1.7875)

= (1.875 + 3.575)

= 5.45 m²

(ii)

Cost of 1 m² of the sheet = Rs 20

cost of 5.45 m² of the sheet will be,

= 5.45 * 20

= 109

Hope it helps!

Answer 2

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 1m2 costs ₹20.

Answer :-

(i) Here, length (l) = 1.5 m, bread th(b) = 1 .25 m

and height (h) = 65 cm = 65/100 m = 0.65 m

∵ It is open from the top.

∴ Its surface area

= [Lateral surface area] + [Base area]

= [2(1 + b)h] + [lb]

= [2(1.50 + 1.25)0.65] m2 + [1.50 x 1.25] m2

= [2 x 2.75 x 0.65] m2 + [1.875] m2

= 3.575 m2+ 1.875 m2 = 5.45 m2

∴ Area of the sheet required for making the box = 5.45 m2

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

Cost of 5.45 m2 sheet = Rs. (20 x 5.45)

= Rs. 109

Hence, cost of the required sheet = Rs. 109

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