a swimmer capable of a water speed of 4km/hr crosses a river that is flowing at 2km/hr. if the river is 130m wide, what is the minimum time required to cross the river (in seconds)

Question

anonymous · Answer

117 seconds

anonymous · Answer

he'll cross the width in min. time,practically speaking, when he uses his entire capabilities to ONLY cross the river. ie his focus is swimming straight and only straight,so that he advances towards the other bank at the fastest pace possible. ie min. t req. = 130m / 4km/hr. (i have assumed river flows perpendicular to its width).