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 = $latex \frac{1}{2}(4+5)&s=1$ $latex => \frac{9}{2} = 4.5 kmph&s=1$ Speed of current = $latex \frac{1}{2}(5-4)&s=1$ $latex => \frac{1}{2} = 0.5 kmph&s=1$ Hence option [D] is the right answer.

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