A boat can move upstream at 25 kmph and downstream at 30 kmph, then the speed of the current is?  Choose the correct choice from the following answers:
A) 5 kmph	B) 7 kmph	C) 8 kmph	D) 9 kmph	E) 2.5 kmph
US = 25   DS = 30   M = (30 - 25)/2= 
<gadget id="calculator">(30 - 25)/2</gadget>
<output>5/2 = around 2.5</output>
2.5   Answer:2.5 kmph
<result>E</result>
A boat can move upstream at 25 kmph and downstream at 30 kmph, then the speed of the current is?