Correct Answer: Option A
Suppose he move 4 km downstream in x hours. Then,
Speed downstream = (4/x) km/hr.
Speed upstream = (3/x) km/hr
So, 48/(4/x) + 48/(3/x) = 14 or x = ½
So, Speed downstream = 8 km/hr, speed upstream =6 km/hr.
Rate of the stream = ½(8-6) km/hr = 1 km/hr.
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