In 1 hour, a boat goes 11 km along the stream and 5 km against the stream. The speed of the boat in still water (In km/hr) is

8

Speed of boat in still water - x

Speed of stream/current - y

According to the question:

Upstream speed i.e. x - y = 5 km/hr -----(1)

Downstream speed i.e. x + y = 11 km/hr ------(2)

Speed of boat in still water i.e. x = ?

Adding both the equations, we get:

x + y + x - y = 5 + 11

2x = 16

x = 8 km/hr