Question
A motorboat in still water travels at a speed of 36
km/hr. It goes 64 km upstream in 2 hours. The time taken by it to cover the same distance down the stream will be :Solution
Speed of the motorboat upstream = 64/2 = 32 km/hr Let the speed of the current be x km/hr ⇒ 36 – x = 32 ⇒ x = 4 km/hr Speed of motor boat downstream = 36 + 4 = 40 km/hr Time taken to cover 64 km at 40 km/hr = 64/40 = 8/5 hours or 1 hour 36 minutes
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