For bigger boxes :

t = 25 cm, b = 20 cm, h = 5 cm

Total surface area of 1 bigger box = 2(lb + bh + hl)

= 2(25 × 20 + 20 × 5 + 5 × 25) cm^{2 }

= 2 (500 + 100 + 125) cm^{2} = 1450 cm^{2 }

Area of cardboard required for overlaps

= 5% of 1450 cm2 = 1450x 5 /100 × cm^{2} = 72.5 cm^{2.}

Total area of cardboard needed for 1 bigger box

= (1450 + 72.5) cm^{2} = 1522.5 cm^{2 }

Total area of cardboard needed for 250 bigger boxes = 1522.5 × 250 cm^{2 }

= 380625 cm^{2}.

For smaller boxes :

t = 15 cm, b = 12 cm, h = 5 cm

Total surface area of 1 smaller box = 2 (lb + bh + hl)

= 2(15 × 12 + 12 × 5 + 5 × 15) cm^{2 }

= 2 (180 + 60 + 75) cm2 = 630 cm^{2}

Area of cardboard required for overlaps

= 5% of 630 cm^{2} = 630x 5 /100 × cm^{2} = 31.5 cm2

Total area of cardboard needed for 1 smaller box = (630 + 31.5) cm^{2}

= 661.5 cm^{2}

Total area of cardboard needed for 250 smaller boxes

= 661.5 × 250 cm^{2} = 165375 cm^{2 }

Now, total area of cardboard needed for 500 boxes (250 bigger and 250

smaller boxes) = (380625 + 165375) cm^{2} = 546000 cm^{2}

Cost of 1000 cm^{2} of cardboard = Rs 4

∴ Cost of 546000 cm^{2} of cardboard = Rs 4/1000 × 546000 = Rs 2184 Ans