It takes a boat going upstream 11 hours to cover the same distance, as it would cover in 9 hours going downstream. What is the speed of the boat if the speed of the current is 2 km/hr?

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