Question
A boat covers 150 km downstream in the same time it
takes to cover 90 km upstream. If the speed of the stream is 5 km/h, determine the speed of the boat in still water.Solution
ATQ,
Let the speed of boat in still water be 'v' km/h.
So, 150 ÷ (v + 5) = 90 ÷ (v - 5)
Or, 15 × (v - 5) = 9 × (v + 5)
Or, 15v - 75 = 9v + 45
Or, 6v = 120
So, v = 20
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