Answer: 
40 liters
Step-by-step explanation: 
We know that the car travels 150km in 12l of gasoline. To find how many liters of gasoline are need to travel 500km, we simply make a proportion equation. 
First, lets write down what we know . . .
1.) 12L of gas = 150km
2.) ?L of gas = 500km
Now since we have the two proportions, its time to add them into an equation and solve them. In this equation, I will use fraction to compare both.
1.)  
 (Liters on top, km on the bottom)
 (Liters on top, km on the bottom)
2.) 
 (Solve the equation using cross-muliplication)
 (Solve the equation using cross-muliplication)
3.) 150 × X = 12 × 500 (Cross multiplied)
4.) 150x = 6000 (Solve Algebraically)
5.) 
 (Divide both sides by 150 to cancel out the 150 (rule))
 (Divide both sides by 150 to cancel out the 150 (rule))
6.) x = 40 (Answer)
Your Welcome,
-Expert Chicken Sama