A boat can move upstream at 50 kmph and downstream at 20 kmph, then the speed of the current is?	Options
A) 5	B) 9	C) 5	D) 15	E) 12
US = 50   15S = 20   M = (50- 20)/2= 
<gadget id="calculator">(50- 20)/2</gadget>
<output>15</output>
15   Answer: 15
<result>D</result>
A boat can move upstream at 50 kmph and downstream at 20 kmph, then the speed of the current is?