In 1 hour, a boat goes 6 km along the stream and 12 km against the stream. The speed of the boat in still water (in km/hr) is : Pick:
A) 3 km/hr.
B) 2 km/hr.
C) 6 km/hr.
D) 8 km/hr.
E) 9 km/hr.
Speed in still water = 1/2(6 + 12) km/hr   = 9 km/hr. ANSW9 km/hr.R :9 km/hr.
<result>E</result>
In 1 hour, a boat goes 6 km along the stream and 12 km against the stream. The speed of the boat in still water (in km/hr) is :