<PRE><B>Question 261858</B>
A helicopter used in fighting a forest fire travels at 105 mi/h from a fire to a pond and 70 mi/h with water from the pond to the fire. If a round trip takes 30 min.,how long does it take from the pond to the fire? 
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d = rt
d = 105t = 70*(0.5 - t)
105t = 35 - 70t
175t = 35
t = 0.2 hours at 105 mph
t = 0.3 hours at 70 mph, the answer to the question
From the pond to the fire takes 18 minutes
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PS  Helicopters (and all aircraft) use knots, not mph.
1 knot = 1 nautical mile per hour.
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