Question 1056020


A paddle boat can move at a speed of 2 ​km/h in still water. The boat is paddled 14
 
km downstream in a river in the same time it takes to go 7 km upstream. What is the speed of the​ river?
<pre>Let speed of the current be C
We then get: {{{14/(2 + C) = 7/(2 - C)}}}
14(2 - C) = 7(2 + C) ------- Cross-multiplying
28 – 14C = 14 + 7C
– 14C – 7C = 14 – 28 
– 21C = - 14
C, or rate of current = {{{highlight_green(matrix(1,4, (- 14)/(- 21), or, 2/3, "km/h"))}}}