It calculates purchasing gas or diesel fuel in the US based on cost per gallon in US dollars, the currency exchange rate from CAD (Canadian dollar) to USD ( US Dollar) converted to cost in Canadian dollars per gallon and litre.
Price of gas fluctuates, as does the currency exchange.
The price of one gallon of gas in the US = $2.78 One CAD exchanged to USD = $1.28 CAD (it cost $1.28 for $1.00 USD) One US gallon = 3.785 litres One litre = 0.264 172 US gallon the price of one gallon of gas in CAD = 2.78 * 1.28 = $ 3.56 the price of one litre of gas in USD = 2.78 / 3.785 = $ 0.73 the price of one litre of gas in CAD = 0.73 * 1.28 = $ 0.94And the story's moral: It is cheaper buying your gas in the United States!! (at this time)