a man can row 18 kmph in still water.it takes him thrice as long to row up as to row down the river.find the rate of stream.	Pick:
A) 2 km/hr  B) 3 km/hr  C) 7 km/hr  D) 9 km/hr  E) 5 km/hr
Let manâ€™s rate upstream be x kmph.then ,his rate downstream=3xkmph.   So,2x=18 or x=9.   Rate upstream=9 km/hr,rate downstream=27 km/hr.   Hence,rate of stream=1/2(27-9)km/hr=9 km/hr.   ANSWER 9 km/hr
<result>D</result>
a man can row 18 kmph in still water.it takes him thrice as long to row up as to row down the river.find the rate of stream.