15 State the parallelogram law of vectors. A man
can row at 6 kmhr' in still water and wants to
cross a river to a position exactly opposite his
starting point. If the river is 5 km wide and is
flowing at 4 kmhr eastwards, find by scale
drawing or otherwise the direction in which he
must set off in order to accomplish his objective.
How long will it take to cross the river?
of swimming at 14 ms¹
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