Question
A swimmer swims from a point A against a current for 12
minutes and then swims backwards in favour of the current for next 12 minutes and comes to the point B. If AB is 200 metres, the speed of current (in km per hour) isSolution
OA = distance covered by upstream speed in 12 minutes = 12/60 (x – y ) OB = distance covered by downstream speed in 12 minutes = 12/60 (x + y ) According to the question, OB – OA = AB 12/60 (x + y ) - 12/60 (x - y ) = 200/1000 1/5 (x + y - x + y) = 200/1000 2y = 2/10 × 5 y = 0.5 km/hr. Speed of current = 0.5 km/hr.
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