A man can swim in still water at 9 km/h, but takes twice as long to swim upstream than downstream. The speed of the stream is?  Pick one:
A) 3 B) 7.5 C) 2.25 D) 1.5 E) 4
M = 9   S = x   DS = 9 + x   US = 9 - x   9 + x = (9 - x)2   9 + x = 18 -2x   3x = 9   x = 3   3NSWER:3
<result>A</result>
A man can swim in still water at 9 km/h, but takes twice as long to swim upstream than downstream. The speed of the stream is?