a.
The rate of the plane in still air is 700 km/h
Let V = rate of plane in still air and v = rate of wind.
When flying against the wind, an airplane travels 5220 kilometers in 9 hours, we have that since distance = speed × time
(V - v) × 9 = 5220
V - v = 5220/9
V - v = 580 (1)
Also, flying with the wind, the same plane travels 6560 kilometers in 8 hours, we have that since distance = speed × time
(V + v) × 8 = 6560
V + v = 6560/8
V + v = 820 (2)
Adding equations (1) and (2), we have
V - v = 580 (1)
+
V + v = 820 (2)
2V = 1400
V = 1400/2
V = 700 km/h
So, the rate of the plane in still air is 700 km/h.
b.
The rate of the wind is 120 km/h
Substituting V into (1), we have
V - v = 580 (1)
700 - v = 580
v = 700 - 580
v = 120 km/h
So, the rate of the wind is 120 km/h
Learn more about rate of plane here:
https://brainly.com/question/18848032
