What is the speed of the stream if a canoe rows upstream at 4km/hr and downstream at 12km/hr  Choose the most appropriate option:
A) 1 kmph B) 4 kmph C) 3 kmph D) 2 kmph E) 1.9 kmph
Sol.   Speed of stream = 1/2(12 - 4) kmph = 4 kmph.   Answer 4 kmph
<result>B</result>
What is the speed of the stream if a canoe rows upstream at 4km/hr and downstream at 12km/hr