Problema Solution
a man takes 2/3 times as long to go 60 miles downstream in his boat as he does to return/ If the boat's speed is 25 mph in still water, find the speed of the current
Answer provided by our tutors
Let
c = the speed of the current, c>=0
r = 25 mph the rate of the boat in still water
The speed of the boat upstream is: r - c = 25 - c
The speed of the boat downstream is: r + c = 25 + c
t = the time of the travel upstream
(2/3)t = the time of the travel downstream
Since distance = speed*time and the boat travels the same distance in each direction we can write:
(25 - c)*t = 60 follows t = 60/(25 - c)
(25 + c)*(2/3)t = 60
Plug t = 60/(25 - c) into (25 + c)*(2/3)t = 60:
(25 + c)*(2/3)(60/(25 - c)) = 60
........
click here to see the equation solved for c
........
c = 5 mph
The speed of the current is 5 mph.