Q. A boat travels 24 km upstream in 6 hours and 20 km downstream in 4 hours. Then the speed of boat in still water and the speed of water current are respectively:
Answer:
4.5 km/hr and 0.5 km/hr
Notes: Rate upstream = 4 kmph
Rate downstream = 5 kmph
∴ Speed of boat in still water = $ \frac{1}{2}(4+5)$
$ => \frac{9}{2} = 4.5 kmph$
Speed of current = $ \frac{1}{2}(5-4)$
$ => \frac{1}{2} = 0.5 kmph$
Hence option [D] is the right answer.