Problema Solution
A boat can travel 26 mph in still water. If it travels 297 miles with the current in the same length of time it travels 171 miles against the current, what is the speed of the current?
Answer provided by our tutors
let
v = 26 mph the speed of the boat in still water, v>0
c = ? speed of a stream
d1 = 297 miles the distance he travels with the current
d2 = 171 miles the distance he travels against the current
t = the time of the travel upstream = the time of the travel downstream
traveling with the current speed: v + c
traveling against the current speed: v - c
since speed = distance/time we have time = distance/speed
traveling with the current
t = d1/(v + c)
t = 297/(26 + c)
traveling against the current
t = d2/(v - c)
t = 171/(26 - c)
by solving the equation
297/(26 + c) = 171/(26 - c)
we find
c = 7 mph is the speed of the current.
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v = 8 mph the speed of the boat in still water
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