A ship at A is to sail to C, 56km north and 258km east of A. After sailing N25°10’E for 120mi to P, the ship is headed toward C. Find the distance of P from C and the required course to mean C.

Answer 1

Use the same method I showed you in your post before this.
The exception here is that you know the final destination to be the ordered pair (258,56)

After converting (120 , N25°10' E) subtract that vector from (258,56)

I am assuming your distance of 120 mi was meant to be 120 km.

BTW, for an alternate solution look at
http://www.jiskha.com/display.cgi?id=1357447890
where the same question was posted and answered before.
Are you the same person, by the exact typing error and use of "mean" for C I assume you are.