What is the price of 1 gallon of gasoline in U.S. dollars in France?

Question

The value of the Euro is currently $1.29 U.S. and the price of 1 liter of gasoline in France is 1.44 Euro.

Answer 1

One of the better ways to solve these kinds of "unit" conversion problems is to start with what you "know" as a fraction (one number over another), and then use the given conversions to "cancel out" units from what you know, and "covert" it into the form you need the answer in.

So you start by knowing the price of 1 liter of gas in Euros, and we want to known the equivalent price of 1 gallon in US Dollars. So it starts like this:

1.44 Euro ????? US Dollars

------------ x ------------- x ------------- = --------------------------

1 liter-Gas 1 Gallon - Gas

So we need to cancel out the Euros for Dollars, and cancel the liters for Gallons.

To switch Euro's to Dollars, we see we need Euro's in the denominator of the conversion and Dollars in the numerator. Similarly, we need liters in the numerator of the conversion and Gallons in the denominator, or something like this

1.44 Euro ???? Liters ???? Dollars ????? US Dollars

------------ x -------------------- x ------------------- = --------------------------

1 liter-Gas 1 Gallons ???? Euros 1 Gallon - Gas

And you can see how the units will cancel if you set it up this way. But this process of including the units as part of the calculations can be a very effective way of solving Chemistry as this works for molar conversions in balancing equations and solution concentrations.

So if you can find the conversion ratio for liters per gallon, and take the information about the Dollar/Euro exchange rate (given in the problem), the rest is just a calculator problem. I hope this helps. John