Question
If a man rows 8km downstream in 6 hours and 4km upstream
in 4 hours, then how long will it take him to cover 14km in still water?Solution
Distance in downstream = 8km Time taken = 6 hours Rate of downstream (a) = distance/timeĀ =Ā 4/3 km/hr Distance covered in upstream = 4km Time taken = 4 hours Rate of upstream (b) = distance/timeĀ =Ā Ā 1km/hr Speed in still water = 1/2(a+b) = 1/2(4/3+1)Ā = 7/6 km/hrĀ Time taken to cover (14km) in still water = distance/time = 14/(7/6) = 12 hours
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