Answer:
- Speed of the plane in still air is 540 mph,
- Speed of the wind is 70 mph
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Let the speed of plane is x and speed of the wind is y.
The speed of the plane with the wind is x + y and speed of the plane against the wind is x - y.
Equation for speed:
Since the same amount of time spent in both cases, we can set equations:
- x + y = 3355/5.5 ⇒ x + y = 610
- x - y = 2585/5.5 ⇒ x - y = 470
Add up the two equations and solve for x:
- x + y + x - y = 610 + 470
- 2x = 1080
- x = 540
Find y:
- 540 + y = 610
- y = 610 - 540
- y = 70