<PRE><B>Question 60758</B>
The speed of a stream in 5 mph. If a boat travels 82 miles downstream in the same time that it takes to travel 41 miles upstream, what is the speed of the boat in still water?
:
SInce the times are given as equal we can make a time equation:
Let s = speed in still water:
(s+5) = speed down stream
(s-5) = speed up stream
time = dist/speed
:
{{{82/(s+5)}}} = {{{41/(s-5)}}}
:
Cross mult and you have:
82(s-5) = 41(s+5)
82s - 410 = 41s + 205
82s - 41s = 205 + 410
41s = 615
s = 15 mph
:
:
Check solution by finding the time: 82/20 = 41/10 = 4.1 hrs</PRE>