Question 742105
The speed of a boat in still water is 8 km/h. It travels 60 km upstream and 60 km downstream in a total time of 16 hours. What is the speed of the stream?
-------------
Avg speed of a round trip = 2*r1*r2/(r1+r2) = 120/16 = 7.5
2*(8-c)*(8+c)/16 = 7.5
{{{64 - c^2 = 60}}}
{{{c^2 = 4}}}
c = 2 km/hr