to #a):

Use a coordinate system: Let the direction of the current be the positive x-axis, then the direction in which the fish is swimming forms the positive y-axis:

.... and ....

Then the resulting velocity is

....I've got

Calculate the length of the vector. If then ....I've got

to #b): This question has to be done in exactly the same way.

to #2:

Do you mean W55°N or do you mean N55°W? I'll take the first version. If this is wrong then you know at leasthowto do the problem.

Use a coordinate system according the geographical directions. The positive x-axis is pointing East, the positive y-axis is pointing North.

Then the first part of the way of the fox is:

........... and the second part is:

The displacement is ..........I've got