Answer:
20 km/hr
Explanation:
time taken by the boat going upstream = 11 hours
time taken for downstream movement = 9 hours
speed of the current = 2 km/h
distance traveled by the boat = d
Assume the speed of boat be x
we know,
distance = speed × time
moving upstream
distance = speed × time
d = (x -2) × 11
downstream
d = (x+2) × 9
now
(x+2) × 9 = (x -2) × 11
2 x = 40
x = 20 km/hr
hence, the speed of the boat will be 20 km/hr