A man swims downstream 70 km and upstream 30 km taking 10 hours each time; what is the speed of the current?  Select the correct option: A) 1 B) 4 C) 2 D) 6 E) 8
70 --- 10 DS = 7   ? ---- 1   30 ---- 10 US = 3   ? ---- 1 S = ?   S = (7 - 3)/2= 
<gadget id="calculator">(7 - 3)/2</gadget>
<output>2</output>
2   Answer: 2
<result>C</result>
A man swims downstream 70 km and upstream 30 km taking 10 hours each time; what is the speed of the current?