When an aircraft flies between two cities, it takes 5h to go downwind and 6h to go upwind. The known wind speed is 24km / h, so the distance between two cities can be calculated Using linear equation of one variable

When an aircraft flies between two cities, it takes 5h to go downwind and 6h to go upwind. The known wind speed is 24km / h, so the distance between two cities can be calculated Using linear equation of one variable

Let s be the distance between the two cities,
（S/5）-24 = （S/6）+24
The solution is s = 1440km

The fuel carried by an aircraft can fly for up to 6 hours. For flight training, when going downwind, it can fly 1500 kilometers per hour; when returning upwind, it can fly 1200 meters per hour. How long does the aircraft have to fly back at most?

If the speed ratio is 1500:1200 = 5:4, then the time ratio is 4:5, 6 × 45 + 4 = 6 × 49 = 83 (hours). A: if the aircraft flies for 83 hours at most, it has to fly back