4. In one hour, a boat goes 11 km/hr along the stream and 5 km/hr against the stream. The speed of the boat in still water (in km/hr) is:
A. 9 km/hr
B. 8 km/hr
C. 3 km/hr
D. 5 km/hr
4. In one hour, a boat goes 11 km/hr along the stream and 5 km/hr against the stream. The speed of the boat in still water (in km/hr) is:
A. 9 km/hr
B. 8 km/hr
C. 3 km/hr
D. 5 km/hr