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  `1 GBP approx 1.328 USD.` 

Also we need to know how many liters are in one gallon, it is about  `3.785.`

Now we can perform the calculations: `8.91` gallons are about  `8.91*3.785` liters, they cost about  `8.91*3.785*1.98` pounds, and in dollars it will be

`8.91*3.785*1.98*1.328,`  which is equal to about  88.68 U.S. dollars.