Let x be the velocity of the wind, then
(310+x) = plane speed downwind
(310-х) = plane speed upwind
[tex] \frac{185}{310+x} = \frac{125}{310-x} \\ 185(310-x)=125(310+x) \\ 57350-185x=38750+125x \\ 57350-38750=125x+185x \\ 18600=310x \\ x=60 \ mph[/tex]
Answer: 60 mph.
