Question
Speed of a boat in still water is 12 kmph and speed of
stream is 9 kmph. A man rows to a place at a distance of 63 km and come back to starting point. The total time taken by him is:Solution
Rate upstream = 12 – 9 = 3 kmph Rate downstream = 12 + 9 = 21 kmph Time taken to go upstream = 63/3 = 21 hr Time taken to go downstream = 63/21 = 3 hr Total time = 21 + 3 = 24 hrs
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