Question
A boat can travel 38 km downstream in 57 min. The ratio
of the speed of the boat in still water to the speed of the stream is 3: 2. How much time will the boat take to cover 22 km upstream?Solution
Speed of downstream = D/T = 38 × (60/57) = 40 km/hr The ratio of the speed of the boat in still water to the speed of the stream = 3: 2 (3x, 2x) => 5x = 40 => x = 8 Speed of upstream = 3x – 2x = x = 8 km/hr Distance = 22 km Time = D/S = 22/8 = 2(3/4) hr = 2 hour 45 min
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