Compare the cost of cooking with LPG versus induction.
Each cooking method's energy use is priced at its own rate, letting you compare the two directly.
LPG cost: Energy used (kg) × LPG price per kg
Induction cost: Energy used (kWh) × electricity rate
Which is generally cheaper, LPG or induction?
It depends on your local LPG and electricity prices, which are different in each region and change over time. There is no single right answer, which is exactly why comparing them directly is useful.