A boat can move upstream at 30 kmph and downstream at 35 kmph, then the speed of the current is?  Choose the correct choice from the following
A) 5
B) 2.5
C) 7
D) 4
E) 32
US = 30   DS = 35   M = (35 - 30)/2= 
<gadget id="calculator">(35 - 30)/2</gadget>
<output>5/2 = around 2.5</output>
2.5   Answer: 2.5
<result>B</result>
A boat can move upstream at 30 kmph and downstream at 35 kmph, then the speed of the current is?