Speed of a boat in still water to speed of boat in upstream is 7:5. If the boat can travel 360 km in downstream in 5 hours, then find the time taken by the boat to cover 28 km in still water.
Let speed of boat in still water and speed of boat in upstream be ‘7x’ km/h and ‘5x’ km/h, respectively. Speed of stream = 7x – 5x = 2x km/h Speed of boat in downstream = 7x + 2x = 9x km/h So, 9x = 360/5 = 72 Or, x = 8 Speed of boat in still water = 7 × 8 = 56 km/h Desired time = 28/56 = 30 minutes
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