Question 1186383
b, boat speed
5, river speed

<pre>
          SPEEDS     TIME             DISTANCE

UP         b-5       12/(b-5)           12

DOWN       b+5       10/(b+5)           10

TOTAL                 5
</pre>
Make the time sum equation.

{{{12/(b-5)+10/(b+5)=5}}}
Simplify and solve.