Question
A motorboat in still water travels at a speed of 32
km/hr. It goes 54 km upstream in 2 hour 15 minutes. The time taken by it to cover the same distance down the stream will be :Solution
Speed of the motorboat upstream = 54/(9/4) = 24 km/hr Let the speed of the current be x km/hr ⇒ 32 – x = 24 ⇒ x = 8 km/hr Speed of motor boat downstream = 32 + 8 = 40 km/hr Time taken to cover 54 km at 40 km/hr = 54/40 = 27/20 hours or 1 hour 21 minutes
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