SOLUTION: An airplane makes the 2,400 miles trip from Washington, DC to San Francisco in 7.5 hours and makes the return trip in 6 hours. Assuming that the plane travels at a constant airspe

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Question 987541: An airplane makes the 2,400 miles trip from Washington, DC to San Francisco in 7.5 hours and makes the return trip in 6 hours. Assuming that the plane travels at a constant airspeed and that the wind blows at a constant rate from west to east, find the plane's airspeed and the wind rate.
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
r, plane's speed when no wind
w, speed of wind
t, time going DC to San F.
x, time back, San F. to DC
d, one-way distance
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FIND r and w;
system%28t=7.5%2Cx=6%2Cd=2400%29

Uniform Rates Rule for Travel: RT=D relates rate, time, and distance.
From DC to San Francisco, travel is AGAINST the wind.
Returning from San Francisco TO DC, travel is WITH the wind. 
                      speed    time     distance
Wash DC to S.F.       r-w       t        d
S.F. back to DC       r+w       x        d

system%28%28r-w%29t=d%2C%28r%2Bw%29x=d%29
Solve for r and w.