When an aircraft flies between the two cities, the wind speed is 24 km / h, it takes 2 hours and 50 minutes to fly against the wind, and it takes 3 hours to fly against the wind to calculate the speed of the aircraft when there is no wind
2 hours 50 minutes = 2 hours 5 / 6 = 17 / 6 hours
If the speed of the aircraft is x when there is no wind, then the downwind speed is x + 24 and the upwind speed is x-24
be
(X+24)*17/6 =(X-24)*3
(X+24)*17=18(X-24)
17X+408=18X-432
X = 840 km / h