Here, 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 m^{2} + 2 (1.25 × 0.65 + 0.65 × 1.5) m^{2 }

= 1.875 + 2 (1.7875) m^{2 }

= (1.875 + 3.575) m^{2} = 5.45 m^{2 }

Hence, 5.45 m^{2} of sheet is required **Ans. **

(ii) Cost of 1 m^{2} of the sheet = Rs 20

∴ cost of 5.45 m^{2} of the sheet = Rs 20 × 5.45 m^{2} =** Rs 109 Ans**