SOLUTION: The speed of a plane is 120 miles/hour in a calm. With the wind it can cover a certain distance in 4 hours, but against the wind it can cover only 3/5 of that distance in the same

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: The speed of a plane is 120 miles/hour in a calm. With the wind it can cover a certain distance in 4 hours, but against the wind it can cover only 3/5 of that distance in the same      Log On


   

Question 667753: The speed of a plane is 120 miles/hour in a calm. With the wind it can cover a certain distance in 4 hours, but against the wind it can cover only 3/5 of that distance in the same time. Find the velocity of the wind.
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
velocity of wind = x mi/h
with wind speed of plane = 120 +x mi/h
D1= (120+x)*4
against wind speed = 120-x mi/h
D2= (120-x)*4
D2= 3/5 D1
3/5(120+x)*4 = (120-x)*4
3(120+x)=5(120-x)
360+3x=600-5x
8x= 240
x=30
wind speed = 30 mi/h