A boat can move upstream at 40 kmph and downstream at 56 kmph, then the speed of the current is?  Choose the correct choice.
A) 5	B) 6	C) 8	D) 4	E) 2
US = 40   DS = 56   M = (56 - 40)/2= 
<gadget id="calculator">(56 - 40)/2</gadget>
<output>8</output>
8 Answer:8
<result>C</result>
A boat can move upstream at 40 kmph and downstream at 56 kmph, then the speed of the current is?