An aircraft travels 1400 km at a speed of 700 km/h

and then runs into a headwind that reduces its speed

over the ground to 500 km/h for the next 800 km.

What is the total time for the flight? What is the

average speed?

Total time of flight = 3.6 hours

Speed of flight = 611.1 Km/h

Explanation:

Time taken when moving at 700 Km/h

Since speed=distance/time then time=distance/speed=1400 Km/700 km/h=2 hours

Time taken when moving at a speed of 500 Km/h

Time=800 km/500 Km/h=1.6 hours

Total time taken=2 hours + 1.6 hours=3.6 hours

Total distance covered = 1400 Km + 800 Km=2200 Km

Average speed=distance/total time taken=2200 km/3.6 hours=611.1 Km/h

Therefore, average speed is 611.1 Km/h