In 1 hour, a boat goes 10 km along the stream and 12 km against the stream. The speed of the boat in still water (in km/hr) is :	Choose the correct choice from the following answers:
A) 3 km/hr.
B) 2 km/hr.
C) 11 km/hr.
D) 8 km/hr.
E) 5 km/hr.
Speed in still water = 1/2(10 + 12) km/hr   = 11 km/hr. ANSWER :11 km/hr.
<result>C</result>
In 1 hour, a boat goes 10 km along the stream and 12 km against the stream. The speed of the boat in still water (in km/hr) is :