Answer:
55.734 mph
Step-by-step explanation:
Let's call the wind speed x and the time of flight t.
Then, we can write the following equation, knowing that the distance is equal speed times time of flight:
910 = (350+x) * t
660 = (350-x) * t
If we isolate t in both equations and compare its value, we have that:
910 / (350+x) = 660 / (350-x)
(350+x)/(350-x) = 910/660
350 + x = 1.3788 * (350-x)
350 + x = 482.58 - 1.3788x
2.3788x = 132.58
x = 55.734 mph