A man swims downstream 72 km and upstream 45 km taking 9 hours each time; what is the speed of the current?  Choose the correct choice:
A) 3 kmph  B) 1.5 kmph  C) 13 kmph  D) 6.5 kmph  E) 7.5 kmph
72 --- 9 DS = 8   ? ---- 1   45 ---- 9 US = 5   ? ---- 1 S = ?   S = (8 - 5)/2= 
<gadget id="calculator">(8 - 5)/2</gadget>
<output>3/2 = around 1.5</output>
1.5   ANSWER:1.5 kmph
<result>B</result>
A man swims downstream 72 km and upstream 45 km taking 9 hours each time; what is the speed of the current?