<PRE><B>Question 1205974</B>
A small airplane can travel 210 mph in still air. The plane can fly 520 miles with the wind in the same time that it can travel 320 miles against the wind.
Find the speed of the wind.

let the speed of wind be x mph

A small airplane can travel 210 mph in still air

Distance traveled = 520 miles

With wind the speed of plane will be (210 +x) mph 
With wind time = distance/ speed =520/ (210+x) hours

Against wind the plane will travel  (210-x) mph
Against wind the time is 320/(210-x) hours

Time is same to and fro.

520/(210+x) = 320/(210-x)

divide by 10

32(210+x) = 52(210-x)

6720 +32x = 10920-52x

84x = 4200

x = 50 

wind speed = 50 mph








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