A man swims downstream 72 km and upstream 45 km taking 3 hours each time; what is the speed of the current?	Choose the most appropriate option:	A) 1.5	B) 3.5	C) 4.5	D) 2.5	E) 5.5
72 --- 3 DS = 24   ? ---- 1   45 ---- 3 US = 15   ? ---- 1 S = ?   S = (24 - 15)/2= 
<gadget id="calculator">(24 - 15)/2</gadget>
<output>9/2 = around 4.5</output>
4.5   Answer:4.5
<result>C</result>
A man swims downstream 72 km and upstream 45 km taking 3 hours each time; what is the speed of the current?