Answer: Relative velocity of the boat with respect to shore is 20 km/h.
Explanation;
Relative velocity of the river with respect to shore,V = 10 km/h
Velocity of the shore = 0 km/h
Relative velocity of the river with respect to shore:


Velocity of the river
= 10 km/h
Velocity of the boat =
= ?
Relative velocity of the boat with respect to river ,V'= 10 km/h



Velocity of the boat
= 20 km/h
Relative velocity of the boat with respect to shore, V":

Relative velocity of the boat with respect to shore is 20 km/h.