If a boat goes 6 km upstream in 90 minutes and the speed of the stream is 3 kmph, then the speed of
the boat in still water is	Options:
A) 12 kmph
B) 7 kmph
C) 14 kmph
D) 15 kmph
E) None of these
Explanation:   Rate upstream = (6/90)*60= 
<gadget id="calculator">(6/90)*60</gadget>
<output>4</output>
4 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 = 4 or x = 7 kmph   Answer: 7 kmph
<result>B</result>
If a boat goes 6 km upstream in 90 minutes and the speed of the stream is 3 kmph, then the speed of
the boat in still water is