If a boat goes 6 km upstream in 30 minutes and the speed of the stream is 3 kmph, then the speed of
the boat in still water is
Choose one:
A) 12 kmph
B) 13 kmph
C) 14 kmph
D) 15 kmph
E) None of these
Explanation:   Rate upstream = (6/30)*60= 
<gadget id="calculator">(6/30)*60</gadget>
<output>12</output>
12 kmph.   Speed of stream= 3 kmph.   Let speed in still water is x km/hr   Then, speed upstream = (x ï¿½3) km/hr.   x-3 = 12 or x = 15 kmph   Answer: 15 kmph
<result>D</result>
If a boat goes 6 km upstream in 30 minutes and the speed of the stream is 3 kmph, then the speed of
the boat in still water is