SOLUTION: An airplane whose speed in still air is 760 km/h can travel 2000 km with the wind in the same amount of time that it takes to fly 1800 km against the wind. What is the wind speed?

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: An airplane whose speed in still air is 760 km/h can travel 2000 km with the wind in the same amount of time that it takes to fly 1800 km against the wind. What is the wind speed?       Log On


   

Question 133375: An airplane whose speed in still air is 760 km/h can travel 2000 km with the wind in the same amount of time that it takes to fly 1800 km against the wind. What is the wind speed?
Algebra 1, systems of linear equations
Answer by vleith(2983) About Me  (Show Source):
You can put this solution on YOUR website!
Given: Still speed of 760km/hour. Can travel 2000km with the wind in the same time as it can go 1800km against the wind.
Let w = windspeed.
distance+=+velocity+%2A+time
2000+=+%28760%2Bw%29+%2A+t+
+%28%282000%29%2F+%28760%2Bw%29+%29+=+t+ with the wind
distance+=+velocity+%2A+time
+1800+=+%28760-w%29+%2A+t+
+%281800%2F+%28760-w%29%29+=+t against the wing
t is the same in both cases, so
%282000%29%2F%28760+%2Bw%29+=+%281800%29%2F%28760-w%29
+%282000%29%28760-w%29+=+%281800%29%28760%2Bw%29+
+%28200%29%28760%29+=+3800+w+
w+=+40+
Check your answer. 2000/(760+40) = 2.5
1800/(760 -40) = 2.5 Check!