Question
In still water, boat ‘X’ is three times as fast as boat
‘Y’. Boats ‘X’ and ‘Y’ are 240 km apart in a stream and are moving towards each other. They meet after 4 hours. What is the speed of boat ‘Y’ in still water, assuming they started at the same time?Solution
ATQ,
Let the still water speed of boat ‘Y’ = ‘y’ km/h
Then, still water speed of boat ‘X’ = 3 × y = ‘3y’ km/h
Let the speed of the stream = ‘x’ km/h
One boat is moving upstream and the other downstream,
So, effective relative speed = 3y + y = ‘4y’ km/h
Now, 4y = 240 ÷ 4 = 60
So, y = 60 ÷ 4 = 15
Speed of boat ‘Y’ in still water = 15 km/h
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