I also need help with this: The market-leading electric car costs $100 000 upfront, whereas a petrol car could cost $24 800. Petrol costs would be $1 725 per year, whereas an electric car takes $650 per year to charge. A wealthy benefactor is willing to pay half the upfront and energy costs if you go for the electric car. I need to figure out how many years it would take for both of them to be that same.