<PRE><B>Question 953679</B>
Since it takes 2 hours to cover 1000 miles, that is 1000/2 = 500 mile per hour. And coming back against the same wind, the speed is 1000/2.5 = 400 miles per hour.

Let a be the air speed and w the wind speed:

a + w = 500
a – w = 400 Let’s add the two equations:
a + w + a – w = 500 + 400 Complete the additions on both sides:
2a = 900
a = 900/2
a = 450 is the plane’s speed in still air. Now substitute in the first equation:
450 + w = 500 Subtract 450 on both sides
w = 50 is the wind speed
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