Question 1005354
a boat travels 1 km upstream and 1 km back. The time for the round trip is 5 hrs. the speed of the stream is 4 km/hr. what is the speed of the boat in still water?
<pre>With S being speed of boat in still water, time equation formed is: {{{1/(S - 4) + 1/(S + 4) = 5}}}, resulting in the quadratic equation: {{{5S^2 - 2S - 80 = 0}}}
This CANNOT be factored, so use the quadratic equation formula, or completing the square to solve for S
Solve for S to get a positive (> 0) solution, or speed of: {{{highlight_green(4.204996879				
)}}} km/h in still water