Question

Set up the equation you would use to solve the problem.Do not actually solve the equation.

A plane flies 390 miles with the wind and 325 miles against the wind in the same length of time. If the speed of the wind is 10 miles per hour, fine the speed of the plane in still air. (Let x = speed of the plane.)

A. 390/x+20 = 395/x

B. 390/x+10 = 325/x-10

C. 390/x = 325/x-20

D. 390/x-10 = 325/x+10

Answer 1

Answer: B

Explanation

I believe it’s B because it says when the plane fly with the wind it’s 390miles so if we want to know the speed of the plane In still air it should be 390/x + 10 because we need to consider that the speed of the plane + the speed of wind. While the plane fly at 325 against the wind so it should be 325/x - 10 cuz this time it goes against the wind.