Question
A boat’s speed in still water is to the stream’s speed
as 7:2. If the boat covers 50.4 km downstream in 96 minutes, find its upstream speed.Solution
ATQ,
Let the speed of boat in still water and speed of stream be 7v and 2v km/h respectively.
So, (7v + 2v) × (96/60) = 50.4
Or, 9v × 1.6 = 50.4
Or, 9v = 31.5
Or, v = 3.5
Therefore, upstream speed = 7v - 2v = 5v = 5 × 3.5 = 17.5 km/h
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