Two surface ships on maneuvers are trying to determine a submarine's course and speed to prepare for an aircraft intercept. Ship A is located at (4,0,0), whereas ship b is located at (0,5,0). All coordinates are given in thousands of feet. Ship A locates the submarine in the direction of the vector 2i+3j-(1/3)k, and ship B locates it in the direction of the vector 18i-6j-k. Four min ago, the submarine was located at (2,-1,-1/3). The aircraft is due in 20 min. Assuming that the submarine moves in a straight line at a constant speed, to what position should the surface ships direct the aircraft?