Question 1206051
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The speed with the wind is plane speed plus wind speed, which is 408/3 = 136mph.<br>
The speed against the wind is plane speed minus wind speed, which is 408/4 = 102mph.<br>
136mph is the plane speed PLUS the wind speed; 102mph is the plane speed MINUS the wind speed; so the difference between the two speeds is twice the wind speed.<br>
Twice the wind speed is 136-102 = 34mph; the wind speed is 17mph.<br>
The speed of the plane is 136-17 = 119mph; or 102+17 = 119mph.<br>