In one hour, a boat goes 19 km along the stream and 5 km against the stream. The speed of the boat in still water (in km/hr) is:
Choose one
A) 2 B) 4 C) 7 D) 12 E) 15
Sol.   Speed in still water = 1/2 (19+5) kmph = 12 kmph.   Answer 12
<result>D</result>
In one hour, a boat goes 19 km along the stream and 5 km against the stream. The speed of the boat in still water (in km/hr) is: