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 1 m2 costs Rs. 20.

Answer 1

Length of plastic box, l = 1.5 m 

breadth b = 1.25 m 

height, h = 65 cm = 0.65 m. 

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

= 1.875 + 1.625 + 1.950 

A= 5.45 m2 . 

(ii) Cost of 1 sq. m sheet is Rs. 20

cost of 5.45 sq.m, sheet is ? 

= 5.45 × 20 

= Rs. 109.