Calculations related to tariff systems.

For a certain power system, the installed capacity is 100 kW, the maximum demand at a certain month is 80 kW, whereas the total energy consumed at this month is 29 MWh. 

1- Find the total monthly bill if a single tariff system is used and the bill constants are 5 $/kW and 0.17 $/kWh

2- Find the total monthly bill if a two part tariff system is used and the bill constants are 5 $/kW and 0.17 $/kWh

3- Find the total monthly bill if a maximum demand tariff system is used and the bill constants are 5 $/kW and 0.17 $/kWh

4- What is the total bill for case 2 and 3 if there is no electricity consumption in this month.