SOLUTION: Use two equations in two variables to solve the application. With the wind, a plane can fly 2,700 miles in 5 hours. Against the same wind, the trip takes 6 hours. Find the airs

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons -> SOLUTION: Use two equations in two variables to solve the application. With the wind, a plane can fly 2,700 miles in 5 hours. Against the same wind, the trip takes 6 hours. Find the airs      Log On


   

Question 1130665: Use two equations in two variables to solve the application.
With the wind, a plane can fly 2,700 miles in 5 hours. Against the same wind, the trip takes 6 hours. Find the airspeed of the plane (the speed in still air).
Answer by ikleyn(52787) About Me  (Show Source):
You can put this solution on YOUR website!
.
Let x be the airspeed of the plane (in miles per hour), and
let y be the speed of the wind.


Then the effective speed of the plane flying with the wind is (x+y) miles per hour,
while its speed flying against the wind is (x-y) mph.


From the condition, the effective speed with the wind is  2700%2F5 = 540 mph.

The effective speed against the wind is  2700%2F6 = 450 mph.


It gives you two equations


x + y = 540    (1)
x - y = 450    (2)


To solve the system, add the equations. You will get

2x = 540+450 = 990  ====>  x = 990/2 = 495.


Answer.  The airspeed of the plane is  495 mph.

Solved.