Let's consider a business that purchases electricity according to the following price tariff: The first 1500 kWh/month is 0.05 S/kWh; Next 2000 kWh/month 0.035S/kWh; Next 3000 kWh/month 0.020 S/kWh; Above 6000 kWh 0.010 S/kWh Let it be given that the monthly electricity consumption amount is 6475 kWh. Calculate the marginal cost of adding 100 kWh to the current consumption according to this price schedule.