A man swims downstream 45 km and upstream 18 km taking 3 hours each time, what is the speed of the man in still water?
Options.
A) 2 B) 8 C) 9 D) 10 E) 10.5
45 --- 3 DS = 15   ? ---- 1   18 ---- 3 US = 6   ? ---- 1 M = ?   M = (15 + 6)/2= 
<gadget id="calculator">(15 + 6)/2</gadget>
<output>21/2 = around 10.5</output>
10.5   Answer: 10.5
<result>E</result>
A man swims downstream 45 km and upstream 18 km taking 3 hours each time, what is the speed of the man in still water?