A man swims downstream 30 km and upstream 18 km taking 3 hours each time, what is the speed of the man in still water?	Choose the correct choice from the following:
A) 9 B) 8 C) 6 D) 1 E) 2
30 --- 3 DS = 10   ? ---- 1   18 ---- 3 US = 6   ? ---- 1 M = ?   M = (10 + 6)/2= 
<gadget id="calculator">(10 + 6)/2</gadget>
<output>8</output>
8   Answer: 8
<result>B</result>
A man swims downstream 30 km and upstream 18 km taking 3 hours each time, what is the speed of the man in still water?