Question 185140
AN AIRPLANE FLEW FOR 4.23 HOURS WITH A 25.5KM/H TAIL WIND.
THE RETURN FLIGHT AGAINST THE SAME WIND TOOK 4.97HOURS.
FIND THE SPEED OF THE PLANE IN STILL WATER.
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w = wind speed = 25.5
r = speed of plane
d = distance
d = rt
Upwind:
d = (r-25.5)*4.97
Downwind:
d = (r+25.5)*4.23
Distance is the same, so they equal each other
(r-25.5)*4.97 = (r+25.5)*4.23
4.97r - 4.97*25.5 = 4.23r + 4.23*25.5
0.74r = 25.5*9.20
r = 317.027 kph
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Planes don't use kilometers per hour, they use knots.  So do boats.
I've flown seaplanes, and that's very fast for on the water.  Maybe you meant in still air.