The current of a stream runs at the rate of 4 kmph. A boat goes 10 km and back to the starting point in 2 hours, then find the speed of the boat in still water?
Select the correct option:	A) A)7	B) B)2	C) C)8.9	D) D)11.4	E) E)3
S = 4   M = x   11.4S = x + 4   US = x - 4   10/(x + 4) + 10/(x - 4) = 2   x = 11.4   Answer:11.4
<result>D</result>
The current of a stream runs at the rate of 4 kmph. A boat goes 10 km and back to the starting point in 2 hours, then find the speed of the boat in still water?