Question 185118
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Distance equals rate times time.  When the plane is going with the wind, ground speed is air speed plus wind speed.  Against the wind, ground speed is air speed minus wind speed.


*[tex \LARGE \ \ \ \ \ \ \ \ \ \  540 = 2(r_a + r_w)]
*[tex \LARGE \ \ \ \ \ \ \ \ \ \  690 = 3(r_a - r_w)]


*[tex \LARGE \ \ \ \ \ \ \ \ \ \  270 = r_a + r_w]
*[tex \LARGE \ \ \ \ \ \ \ \ \ \  230 = r_a - r_w]


Add the equations:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \  500 = 2r_a]


*[tex \LARGE \ \ \ \ \ \ \ \ \ \  r_a = 250]


*[tex \LARGE \ \ \ \ \ \ \ \ \ \  270 = 250 + r_w]


*[tex \LARGE \ \ \ \ \ \ \ \ \ \  r_w = 20]



John
*[tex \LARGE e^{i\pi} + 1 = 0]
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