A boat can move upstream at 25 kmph and downstream at 40 kmph, then the speed of the current is?	Select the correct option:	A) 5	B) 6	C) 7	D) 7.5	E) 32
US = 25   7.5S = 40   M = (40 - 25)/2= 
<gadget id="calculator">(40 - 25)/2</gadget>
<output>15/2 = around 7.5</output>
7.5   Answer: 7.5
<result>D</result>
A boat can move upstream at 25 kmph and downstream at 40 kmph, then the speed of the current is?