Question 374249
let speed of plane in still air be x mph
speed of wind be y mph
time = d/r
with wind time
560/(x+y)=1
x+y =560........................1
...
against wind  time 
480/(x-y)=1

x-y =480........................2

add the two equations (1)&(2)
2x=1040
/2
x=1040/2
x= 520 mph speed of plane in still air
y= 40 mph  speed of wind
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m.ananth@hotmail.ca