In one hour, a boat goes 12 km/hr along the stream and 8 km/hr against the stream. The speed of the boat in still water (in km/hr) is:  Pick one
A) 1 km/hr	B) 2 km/hr	C) 10 km/hr	D) 11 km/hr	E) 12 km/hr
Let speed of the boat in still water = x and speed of the stream = y   Then   x + y = 12   x - y = 8   Adding these two equations, we get 2x = 20   =&gt; x = 10   ie, speed of boat in still water = 10 km/hr   ANSWER:10 km/hr
<result>C</result>
In one hour, a boat goes 12 km/hr along the stream and 8 km/hr against the stream. The speed of the boat in still water (in km/hr) is: