The motion of the ship can be divided into the direction along the river bank and the direction perpendicular to the river bank. In the direction perpendicular to the river bank, there are:

t = Lv = 100 10s = 10s；

The average speed of water flow velocity is equal to the water flow velocity at L4, so the distance along the river bank is:

x=。 ut = 0.2× 1004× 10m = 50m；

So the answer is:10,50.