<PRE><B>Question 998846</B>
.
On an upstream trip, a canoe travels 40 km in 5 hours. Downstream, it travels the same distance in half the time. 
What is the rate of the canoe in still water and the rate of the current?
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On an upstream trip, &amp;nbsp;the canoe speed relative to the river banks is &amp;nbsp;{{{40_km/5_hours}}} = 8 {{{km/h}}}. 


This speed is the difference of the speed of canoe relative water, &amp;nbsp;u, &amp;nbsp;and the speed of current, &amp;nbsp;v:


8 = u - v. &amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;(1)


Downstream, &amp;nbsp;the canoe speed relative to the river banks is twice more: &amp;nbsp;{{{40/2.5}}} = 16 {{{km/h}}}.


This speed is the sum of the speed of canoe relative water, &amp;nbsp;u, &amp;nbsp;and the speed of current, &amp;nbsp;v:


16 = u + v. &amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;(2)


Add &amp;nbsp;(1) &amp;nbsp;and &amp;nbsp;(2). &amp;nbsp;You will get 


2u = 8 + 16 = 24, &amp;nbsp;hence, &amp;nbsp;u = {{{24/2}}} = 12 {{{km/h}}}.

Then &amp;nbsp;v = 4 {{{km/h}}}.


&lt;U&gt;Answer&lt;/U&gt;. &amp;nbsp;The canoe speed in a still water is &amp;nbsp;12 {{{km/h}}}. 

&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;The current speed is &amp;nbsp;4 {{{km/h}}}.

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