So here's gives that
total weight of 25 bags = 50 x 25
= 1250
total cost of 25 bags weighing 50 kg is = 15000
cost of 1 kg = 15000 ÷ 1250 = 12
now total weight of 15 bags weighing 30 kg = 450
cost per kg = 12
cost of 15 bags weighing 30 each = 450 x 12
Answer = 5400 rupees.