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**Hi, I have a homework and I am not sure about some things.**

1. Homework Statement

1. Homework Statement

Person A and person B are next to river. Velocity of river is 1 m/s. There is a person drowning 30 m from shore. He doesn´t move, because there is a something, which he can hold. People A and B are 40 far from him (40 m along river, but 50 m if they swum). Person A is a very good swimmer (1,25 m/s) so he decided to jump into the river and swum across the river to person C. Person B can run 4,75 m/s but swims only 1 m/s. So, he runs and then jumps into the river and swims.

a) What angle should person A swim to person C, in order to be in the shortest time to person C?

b) What time would it take?

c) How much time should person B run (and then jump into the river) to get to person C at the same time as person A?

d) How many m has person B already run on the shore?

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It is pictured in image, which i painted: https://s22.postimg.org/y4v78ilkh/whatever.png

**2. Homework Equations**

v = d/t

Pytagoras sentence (50^2=30^2+40^2)

cos(-1)(0,8)=36,869°

**3. The Attempt at a Solution**

I tried to draw the image in paint.

I counted 50 m with pythagoras sentence.

I can also count the angle of swimmer A (36,87°).

Now, I am not sure how to count velocity of person A. I know velocity of swimmer (1,25 m/s), I know velocity of river (1 m/s). And now to count velocity of swimmer A in river? Should I sum the velocities (1+1,25 = 2,25 m/s) Or is is different because of angle? Now the time will be easy to count (v=d/t). Now I don't know the time, so I can't solve person B.

I enclose image:

https://s22.postimg.org/y4v78ilkh/whatever.png