Question 827580: Write a system of two equations in two variables to solve the problem.
The jet stream is a wind current that flows across the United States from west to east. Flying with the jet stream, an airplane flew 2,448 miles in 4.5 hours. Against the same wind, the return trip took 6 hours. Find the speed of the plane in still air and the speed of the jet stream.
plane in still air = ? mph
jet stream = ? mph
Answer by lwsshak3(11628)   (Show Source):
You can put this solution on YOUR website! Write a system of two equations in two variables to solve the problem.
The jet stream is a wind current that flows across the United States from west to east. Flying with the jet stream, an airplane flew 2,448 miles in 4.5 hours. Against the same wind, the return trip took 6 hours. Find the speed of the plane in still air and the speed of the jet stream.
plane in still air = ? mph
jet stream = ? mph
***
let x=speed of plane in still air
let c=speed of jet stream
(x+c) speed of plane with wind
(x-c) speed of plane against wind
travel time=distance/speed
..
2448/(x+c)=4.5
2448/(x-c)=6
..
4.5x+4.5c=2448
6.0x-6.0c=2448
..
27x+27c=14688
27x-27c=11016
add
54x=25704
x=476
6c=6x-2448
c=68mph
..
speed of plane in still air=476 mph
speed of jet stream=68 mph
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