If Rahul rows 15 km upstream in 3 hours and 21 km downstream in 3 hours, then the speed of the
stream is  Select the correct option.
A) 5 km/hr B) 4 km/hr C) 2 km/hr D) 1 km/hr E) None of these
Explanation:   Rate upstream = (15/3) kmph   Rate downstream (21/3)= 
<gadget id="calculator">(21/3)</gadget>
<output>7</output>
7 kmph.   Speed of stream (1/2)(7 - 5)kmph= 1 kmph   Answer: 1 km/hr
<result>D</result>
If Rahul rows 15 km upstream in 3 hours and 21 km downstream in 3 hours, then the speed of the
stream is