If a person uses 100 units of electricity, 1 LPG cylinder, and 10 litres petrol per month, then how much total energy is used?

To answer this question, we need to know the energy content of each item mentioned: electricity, LPG, and petrol.

1. Electricity: 1 unit of electricity is equal to 1 kilowatt-hour (kWh). Therefore, 100 units of electricity is equal to 100 kWh. The energy content of 1 kWh is approximately 3.6 megajoules (MJ). So, the total energy used from electricity is 100 kWh * 3.6 MJ/kWh = 360 MJ.

2. LPG: 1 LPG cylinder typically contains 14.2 kg of LPG. The energy content of LPG is approximately 46.1 MJ/kg. Therefore, the total energy used from 1 LPG cylinder is 14.2 kg * 46.1 MJ/kg = 654.2 MJ.

3. Petrol: The energy content of petrol is approximately 31.54 MJ/litre. Therefore, the total energy used from 10 litres of petrol is 10 litres * 31.54 MJ/litre = 315.4 MJ.

Adding all these up, the total energy used is 360 MJ (from electricity) + 654.2 MJ (from LPG) + 315.4 MJ (from petrol) = 1329.6 MJ.