Question
The downstream speed of a boat is 75% greater than its
upstream speed, and the speed of the stream is 3 m/s. How far can the boat travel in still water in 7.5 hours?Solution
Let the speed of boat in still water is y m/sec Then according to question (y+3) = 175% of (y-3) 4y+12 = 7y-21 3y = 33 Y = 11 m/sec Y = 11×18/5 km/hrs. = 198/5 km/hrs. boat can cover the distance in still water in 7.5 hours = 198/5 ×7.5 = 297 km
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