Final answer:
To find the speed of the plane in still air and the speed of the wind, we can set up a system of equations using the given information. Solving the equations will give us the required values.
Step-by-step explanation:
To solve this problem, we can use the formula Speed = Distance / Time. Let's call the speed of the plane in still air S and the speed of the wind W. When the plane is flying with the wind, the effective speed is S + W, and when it's flying against the wind, the effective speed is S - W.
Given that the plane takes (7)/(2) hours to travel 1120 miles with the wind, we can set up the equation:
S + W = 1120 / (7/2) = 320 mph
Similarly, when the plane is flying against the wind, it takes 4 hours:
S - W = 1120 / 4 = 280 mph
Now, we can solve these two equations to find the values of S and W. Adding the two equations together, we get:
2S = 600
S = 300
Substituting the value of S back into one of the original equations, we can find the value of W:
300 + W = 320
W = 20
So, the speed of the plane in still air is 300 mph, and the speed of the wind is 20 mph.