A plane used 175.2 liters of gas per hour on a flight. If the flight, lasted 3.5 hours, how many liters of gas were used?

Multiply 175.2 liters/hour times 3.5 hours -
And that is actually NOT ACCURATE -
Because as your airplane gets lighter, it will burn less gas per hour -

So 525.6 liters would not be a correct answer -

Because the first hour you use full power for takeoff and climb to cruise altitude -
Then you have a cruise (how many hours?) -
Then the last hour of cruise, you descend for approach and landing at reduced power -

175.2 * 3.5 = x