Julia pays $56.70 to fill her car with 15 gallons of gas.

Which equation can be used to find c, the cost per gallon?

I'm not sure if there are supposed to be options, but the steps to figuring this problem out are fairly simple. You just divide the cost by the number of gallons. So an equation for that might look like this:

$56.70/15 = c

c = $3.78