arithmetic - a person goes 34 th of a kilometer against the stream in 11 minutes and 15 seconds and along the stream in 7 minutes and 30 seconds find the speed in kmhr of the person in still water is - skillgun

We can write three-quarters of a kilometer as 750 meters,
and 11 minutes as 675 seconds.
Rate upstream = 750/675 m/sec = 10/9 m/sec.
Rate downstream = 750/450 m/sec = 5/3 m/sec.
Rate in still water = (1/2) x (10/9 + 5/3) m/sec
= 25/18 m/sec
= 25/18 x 18/5 km/hr
= 5 km/hr.