Word problem using hyperbola...

Here's a drawing of the provided figure:

http://imgur.com/wrzYH.png

( URL of the picture in case it doesn't display: http://imgur.com/wrzYH.png )

The axes x and y are measured in miles.

In the figure, the LORAN stations at A and B are 520 mi apart, and the ship at P receives station A's signal 2,640 microseconds (ms) before it receives the signal from B.

A) Assuming that radio signals travel at 960 ft/ms, find | d(P, A) - d(P, B)|

B) Find an equation for the branch of the hyperbola indicated in red in the figure, using miles as the unit of distance.

C) If A is due north of B, and if P is due east of A, how far is P from A?