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? Pick
A) 1.7
B) 1.9
C) 1.1
D) 2
E) 1.2
M = 6   S = x   2S = 6 + x   US = 6 - x   6 + x = (6 - x)2   6 + x = 12 -2x   3x = 12-6= 
<gadget id="calculator">12-6</gadget>
<output>6</output>
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?