SOLUTION: A plane flew 1200 miles with a tailwind in 2.5 hours. The return trip against the wind took 3 hours. Find the speed of the wind, find the speed of the plane in still air.

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: A plane flew 1200 miles with a tailwind in 2.5 hours. The return trip against the wind took 3 hours. Find the speed of the wind, find the speed of the plane in still air.      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 325523: A plane flew 1200 miles with a tailwind in 2.5 hours. The return trip against the wind took 3 hours. Find the speed of the wind, find the speed of the plane in still air.
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
Let speed of plane be xmph
speed of wind be y mph
..
with wind speed = x+y
distance = 1200
Time = 1200/x+y = 2.5
1200=2.5x+2.5y................1
..
Against wind speed = x-y
disatnce = 1200
time = 1200/x-y=3
1200= 3x-3y...............2
..
multiply equation 1 by 3 and equation 2 by 2.5
3600=7.5x+7.5y
3000=7.5x-7.5y
By adding the two equations
6600=15x
x=440 mph speed of plane
plug the value of x in the equation 2
1200= 1320-3y
3y=120
y= 40 mph speed of wind