While traveling in England, you purchase 8.91 gallons of gas (or petrol there). The price posted is €1.98 per liter. How many U.S. dollars...

I suppose the prices in England are listed in pounds £, not in euros €.

To answer this question we need the conversion ratio between pounds and U.S. dollars. I got it from the attached link, and it says   

Also we need to know how many liters are in one gallon, it is about  

Now we can perform the calculations: gallons are about   liters, they cost about   pounds, and in dollars it will be

 which is equal to about  88.68 U.S. dollars.