Assume the situations are proportional. Use the unit rate to write an equation, then solve.
A car can travel 476 miles on 14 gallons of gas. Write an equation relating the distance,d, to the number of gallons, g. How many gallons of gas does this car need to travel 578 miles?
The car would be 17 gallons of gas, because the unit rate is 34 miles per gallon. Divide 578 by 34, and there you go! You'll get 17, which is the gallons. You, my friend, have just solved for x.
