Question
Speed of current is equal to 25% of speed of boat in
still water. If the boat takes 14 hours to cover 140 km in still water, then find the time taken by the boat to cover 82.5 km in upstream.Solution
Speed of the boat in still water = 140 ÷ 14 = 10 km/h Speed of current = 10 × 0.25 = 2.5 km/h Therefore, upstream speed of the boat = 10 – 2.5 = 7.5 km/hr Required time taken = 82.5 ÷ 7.5 = 11 hours
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