A man can row upstream 11 kmph and downstream 18 kmph. Find his rate in still water .

 a) 13 km/hr
 b) 14.5 km/hr
 c) 15 km/hr
 d) 17 km/hr

14.5 km/hr. Solution If a is rate downstream and b is rate upstream Rate in still water = 1/2(a+b) ==> Rate in still water = 1/2(18+11) = 14.5 kmph