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**snaes** A guy traveling 5m/s accross a 40m wide river (banks are parallel). The water speed is fastest in the middle. The speed for the water is given as: (3/400)(x)(40-x) where x is the meters from shore. (for ease of communication assue the river goes North and the guy is traveling West to East).

1) How far down does he travel?

2) At what angle South (upstream) does he need to travel to end up directly accross the river from where he started.

My work: It takes him 8 seconds to cross the river because his speed is constant. From here I am not sure where to begin. I am pretty sure that there is an integral involved to "add up" all the downward drif but i cannot get it to work out.

As for the second part this should (i think) be easy because given that it is 40 meter accross and "Z" feet downstream is what he ended up. I can just use tangent to figure out that angle and say to go upstream.