Question
The speed of a boat in still water is 2 times more than
that of the current. If the boat takes 12 hours to cover 144 km upstream, then find the time taken by the boat to cover 480 km downstream.Solution
Let the speed of the current be ‘x’ km/hr
Therefore, speed of the boat in still water = 3x km/hr
According to the question,
3x – x = 144 / 12
Or, 2x = 12
Or, x = 6 km/h
Required time taken = 480 / (3x + x) = 480 / (4 × 6) = 480/24 = 20 hours
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