man can row upstream at 10 kmph and downstream at 20 kmph, and then find the speed of the man in still water?	Options:
A) 5	B) 20	C) 30	D) 25	E) 15
US = 10   DS = 20   M = (10 + 20)/2= 
<gadget id="calculator">(10 + 20)/2</gadget>
<output>15</output>
15   Answer:15
<result>E</result>
man can row upstream at 10 kmph and downstream at 20 kmph, and then find the speed of the man in still water?