a man can row upstream at 40 kmph and downstream at 52 kmph, and then find the speed of the man in still water?  Choose the correct answer:
A) 27
B) 40
C) 42
D) 46
E) 24
<gadget id="calculator">40 + 52</gadget>
<output>92</output>

<gadget id="calculator">92 / 2</gadget>
<output>46</output>

<result>D</result>
a man can row upstream at 40 kmph and downstream at 52 kmph, and then find the speed of the man in still water?
divide(add(40, 52), const_2)
"us = 40 ds = 52 m = ( 40 + 52 ) / 2 = 46 answer : d"