Answer:
the speed of the plane with no wind is 700 km/h and the speed of the wind is 100 km/h
Step-by-step explanation:
Let V be the speed of the plane and v the speed of the wind. Down current, they are in opposite directions, and the plane travels a a distance of 4000 km in 5 hours,so
5(V - v) = 4000
V - v = 800 (1)
For upwind movement, since the plane travels 3000 km in 5 hours, so
5(V + v) = 3000
V + v = 600 (2)
adding equations (1) and (2), we have
V - v = 800
+
V + v = 600
2V = 1400
V = 1400/2 = 700 km/h
subtracting equations (2) from (1), we have
V - v = 800
-
V + v = 600
-2v = 200
v = -200/2 = -100 km/h
So, the speed of the plane with no wind is 700 km/h and the speed of the wind is 100 km/h
