A man can swim in still water at 6 km/h, but takes twice as long to swim upstream than downstream. The speed of the stream is?
Choose the correct choice from the following answers:	A) 3	B) 7.5	C) 2.25	D) 2	E) 4
M = 6   S = x   2S = 6 + x   US = 6 - x   6 + x = (6 - x)2   6 + x = 12 -2x   3x = 6   x = 2   ANSWER:2
<result>D</result>
A man can swim in still water at 6 km/h, but takes twice as long to swim upstream than downstream. The speed of the stream is?