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i need help with a math word problem?
an airplane travels 600 miles against the wind in 5 hours and makes the return trip with the same wind in 2 hours. what is the speed of the wind?
6 Answers
- Alam Ko IyanLv 71 decade agoFavorite Answer
let x = speed of plane
y = speed of the wind
rate = distance/ time
x+y = 300
x-y = 120 ... get the difference:
..............
2y = 180
y = 90 mph.
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let a be the speed of the airplane
let w be the speed of the wind
when the airplane travel against the wind, its resultant speed is a + w. It takes 5 hrs to cover 600 miles
when the airplane returns, this time, it travels with the wind. The resultant speed of the airplane is a - w. It takes 2 hrs to cover 600 miles
distance = speed * time
agaisnt the wind
600 = (a - w) * 5
with the wind
600 = (a + w) * 2
so the a
600 = (a - w) * 5
120 = a - w
a = 120 + w
600 = (a + w) * 2
600 = (120 + w + w) * 2
300 = 120 + 2w
180 = 2w
w = 90
speed of the wind is 90 mi/hr
- Anonymous1 decade ago
Here's your help - set up 2 linear equation and solve them...
The key is that velocity is distance divided by time (like in miles per hour).
If we call the speed of the wind w, then base velocity - w divided by time equals return velocity + w divided by time... Let's see what that gives us....
(600 - w) / 5 = (600 + w)/2
Multiply both sides by 10...
1200 - 2w = 3000 + 5w Now just solve for w (wind speed...)
7w = -1800, or w = -257 MPH (negative means against the 1st direction.)
- Justin DLv 51 decade ago
Sorry I misread the problem. Lets try it again. distance = 600 miles
speed = distance/time
Let x = speed of plane
Let y = speed of wind
(x-y) * 5 hours = 600 miles
(x+y) * 2 hours = 600 miles
x-y = 120 m/h
x+y = 300 m/h
Add the two equations together
2x = 420
x = 210 miles per hour
y = 90 miles per hour
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- 1 decade ago
the speed of the plane is equal to distance /time
so in one case you get a speed of 120mph(against the wind)
and in the other you get a speed of 300mph(withthe wind)
now you set up a system of equations:
x - y = 120
x + y = 300
where x the speed of the plane in no wind, and y is the wind speed.
x=120+y plug this into the second eqn.
120+2y=300 solve for y
y=90mph
- Anonymous1 decade ago
200 mph