A straight river is 20m wide. The velocity of the river at (x,y) is v=[-(3x(20-x))/100]j m/min, 0<=x<=20. A boat leaves the shore at (0,0) and travels through the water with a constant velocity. It arrives at the opposite shore at (20,0). The speed of the boat is always radical 20 m/min.

Find the velocity of the boat.

Find the location of the boat at time t.

Please help! I am really stuck.