The current of a river is 2 miles per hour. A boat travels to a point 8 miles upstream and back again in 3 hours. What is the speed of the boat in still water?
Let the speed of the boat in still water be
Therefore total trip is the sum of the upstream part and the downstream part.
Total distance covered is hence
But since speed = distance/time,
and hence write :
This leads to the quadratic equation in v,
Clearly the latter is impossible and so hence