A man can swim in still water at 15 km/h, but takes twice as long to swim upstream than downstream. The speed of the stream is?	Pick:	A) 3.9	B) 5	C) 5.3	D) 1.5	E) 5.2
M = 15   S = x   DS = 15 + x   US = 15 - x   15 + x = (15 - x)2   15 + x = 30 -2x   3x = 15   x = 5   Answer:5
<result>B</result>
A man can swim in still water at 15 km/h, but takes twice as long to swim upstream than downstream. The speed of the stream is?