If a boat goes 7 km upstream in 42 minutes and the speed of the stream is 4 kmph, then the speed of
the boat in still water is  Choose the correct choice from the following options.
A) 12 kmph
B) 13 kmph
C) 14 kmph
D) 15 kmph
E) None of these
Explanation:   Rate upstream = (7/42)*60= 
<gadget id="calculator">(7/42)*60</gadget>
<output>10</output>
10 kmph.   Speed of stream= 4 kmph.   Let speed in still water is x km/hr   Then, speed upstream = (x ï¿½4) km/hr.   x-4 = 10 or x = 14 kmph   Answer: 14 kmph
<result>C</result>
If a boat goes 7 km upstream in 42 minutes and the speed of the stream is 4 kmph, then the speed of
the boat in still water is