For bigger box:
Length of the bigger box = 20cm
Breadth of the bigger box = 15cm
Height of the bigger box = 5cm
So, Total Surface Area of bigger box = 2(lb + bh + hl)
= 2(20×15 + 15×5 + 5×20)
= 2(300 + 75 + 100)
= 2(475)
= 950cm2
For Smaller box:
Length of the smaller box = 16cm
Breadth of the smaller box = 12cm
Height of the smaller box = 4cm
So, Total Surface Area of bigger box = 2(lb + bh + hl)
= 2(16×12 + 12×4 + 4×16)
= 2(192 + 48 + 64)
= 2(304)
= 608cm2
Total surface area of 200 boxes of each type = 200(950 +608)
= 200 × 1558
= 311600cm2
Extra Area Required = 5% of (950 + 608)
= 5/100 x 1558 x 200
= 15580cm2
So, Total cardboard Required = 311600 + 15580
= 327180cm2
= 327180/1000 = 327.18 m2
Cost of Cardboard for 1m2 = Rs 20
Cost of Cardboard for 327.18 m2 = 20 × 327.18
= Rs 654.36
Hence, the cost of the cardboard for supplying 200 boxes of each kind is Rs 654.36.