<PRE><B>Question 916628</B>
behind it a small plane can fly 240 miles in 3 hours.Fling the same distance into the same wind would take 4 hours.Find the speed of the plane with no wind.
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let x=speed of plane with no wind
let c=speed of wind
(x+c)=speed of plane with wind
(x-c)=speed of plane against wind
travel time*speed=distance
..
3(x+c)=240
4(x-c)=240
..
3x+3c=240
4x-4c=240
..
12x+12c=960 (mult. eq by 4)
12x-12c=720 (mult. eq by 3)
add
24x=1680
x=70
speed of plane with no wind=70 mph</PRE>