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;
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
Solve for r and w.