Answer:
5 km/hr East
Step-by-step explanation:
The resultant velocity when two objects go in opposite direction is given by the sum of the velocities. Given that the river current flows West at 15 km/h but the boat goes East at 20 km/hr, we take East as positive and West as negative. The resultant velocity will be
20-15=5 km/hr
Since velocity must have direction component, and we have final answer as positive, then the direction is East