2015 · Q26
In a flight of 600 km, an aircraft was slowed down due to bad weather. Its average speed for the trip was reduced by 200 km/hr and the time of flight increased by 30 minutes. The duration of the flight is
Elementary MathematicsTime, Speed and Distance
- A1 hour
- B2 hours
- C3 hours
- D4 hours
Explanation
If the scheduled duration is T hours, 600/T − 600/(T + 1/2) = 200. T = 1 satisfies this: at 600 km/h the trip takes 1 h, while at 400 km/h it takes 1.5 h — 200 km/h slower and half an hour longer. So the (scheduled) duration is 1 hour (option A).